Hydrological and hydrochemical response of a small canadian shield catchment to late winter rain-on-snow events

A study was undertaken during the winter of 1990–1991 in a small (3.7 ha) Canadian Shield catchment to examine the hydrological and hydrochemical response during rain-on-snow events. The results are presented of two large (37.9 and 34.6 mm) rain-on-snow events occurring in early and late March 1991. Peak and total runoff and the groundwater response from the two events are significantly different. Hydrological data indicate that these differences can be attributed to a combination of meteorological (temperature) and physical conditions (antecedent snowpack ripeness, soil moisture and groundwater levels). An immature snowpack (low temperature and density) combined with low antecedent soil moisture conditions significantly reduced the magnitude of the net hydrological input and runoff from the catchment during the early March event, whereas a more mature snowpack and high antecedent soil moisture conditions led to a large runoff event during late March. During both rain-on-snow events a significant portion of the pre-event snowpack chemical load was lost. Based on the maximum snowpack chemical load measured before the events, the two large rain-on-snow events and a brief mid-March warm period during which there were two much smaller rain-on-snow events removed 78% of the hydrogen ion and 63% of the sulphate and nitrate load from the snowpack, while only reducing snowpack water equivalence by 7%. A two-component (rain and snowmelt) isotopic (δ¹⁸O SMOW %₀) separation of snowmelt lysimeter water during the two events indicated that snowmelt was an important (50 and 65%, respectively) water source available for infiltration and runoff at the snow-soil interface. Considering the high hydrogen ion loadings to the catchment during these two events (3.3 and 3.0 mequiv.m^?2, respectively) streamflow pH was not significantly reduced due to an increase in the discharge of well-buffered groundwater. A two-component isotopic hydrograph separation of peak stream discharge during the 2–3 March event indicated that 75% of the total flow was groundwater. In mid-latitude acid-sensitive catchments, winter rain-on-snow events are an important hydrological occurrence due to their ability to elute much of the chemical load (H⁺, SO₄, NO₃) from the snowpack before the onset of spring melt when the maximum annual hydrological input typically occurs.     

Seasonal snowpack dynamics and runoff in a cool temperate forest: lysimeter experiment in Niigata,Japan

Seasonal snowpack dynamics are described through field measurements under contrasting canopy conditions for a mountainous catchment in the Japan Sea region. Microclimatic data, snow accumulation, albedo and lysimeter runoff are given through the complete winter season 2002–03 in (1) a mature cedar stand, (2) a larch stand, and (3) a regenerating cedar stand or opening. The accumulation and melt of seasonal snowpack strongly influences streamflow runoff during December to May, including winter baseflow, mid‐winter melt, rain on snow, and diurnal peaks driven by radiation melt in spring. Lysimeter runoff at all sites is characterized by constant ground melt of 0·8–1·0 mm day⁻¹. Rapid response to mid‐winter melt or rainfall shows that the snowpack remains in a ripe or near‐ripe condition throughout the snow‐cover season. Hourly and daily lysimeter discharge was greatest during rain on snow (e.g. 7 mm h⁻¹ and 53 mm day⁻¹ on 17 December) with the majority of runoff due to rainfall passing through the snowpack as opposed to snowmelt. For both rain‐on‐snow and radiation melt events lysimeter discharge was generally greatest at the open site, although there were exceptions such as during interception melt events. During radiation melt instantaneous discharge was up to 4·0 times greater in the opening compared with the mature cedar, and 48 h discharge was up to 2·5 times greater. Perhaps characteristic of maritime climates, forest interception melt is shown to be important in addition to sublimation in reducing snow accumulation beneath dense canopies. While sublimation represents a loss from the catchment water balance, interception melt percolates through the snowpack and contributes to soil moisture during the winter season. Strong differences in microclimate and snowpack albedo persisted between cedar, larch and open sites, and it is suggested further work is needed to account for this in hydrological simulation models. Copyright © 2005 John Wiley & Sons, Ltd.     

Snowmelt and the hydrological interaction of forest–grassland ecosystems in Central Yakutia,eastern Siberia

In the last two decades the major focus of study in forest water and carbon balances in eastern Siberia has been on the effect of rain during the growing season. Little attention has been paid to the contribution of snowmelt water. The results of the present study indicate that weather conditions during the snowmelt period as well as the soil moisture conditions carried from the previous year's growing season strongly determined the water availability for the forest ecosystem at the beginning of the next growing season. In the forest–grassland intermingled ecosystem of lowland Central Yakutia, gradual snowmelt water flow from the forest into the adjacent grassland depressions increased when soil moisture was high and air temperature was low, whereas low soil moisture and high air temperatures accelerated soil thawing and consequently snowmelt water infiltration into the forest soil. We found that snow depth did not determine the volume of snowmelt water moving to the grassland depression since the thermokarst lake water level in the adjacent grassland was about 25 cm lower in 2005 than in May 2006, even though maximum snow depth reached 57 cm and 43 cm in the winter of 2004–05 and 2005–06, respectively. The contribution of snowmelt water to forest growth as well as the flow of water from the forest to the grasslands showed a strong annual variability. We conclude that warmer springs and high variability in precipitation regimes as a result of climate change will result in more snowmelt water infiltration into the forest soil when the previous year's precipitation is low while more snowmelt water will flow into the thermokarst lake when the previous year's precipitation is high. Copyright © 2015 John Wiley & Sons, Ltd.     

Soil frost effects on soil water and runoff dynamics along a boreal forest transect: 1. Field investigations

To determine how soil frost changes flowpaths of runoff water along a hillslope, a transect consisting of four soil profiles directed towards a small stream in a mature forest stand was investigated at Svartberget, near Vindeln in northern Sweden. Soil temperature, unfrozen water content, groundwater level and snow depth were investigated along the transect, which started at the riparian peat, and extended 30 m upslope into mineral soils. The two, more organic‐rich profiles closest to the stream had higher water retention and wetter autumn conditions than the sandy mineral soils further upslope. The organic content of the soil influenced the variation in frost along the transect. The first winter (1995–96) had abnormally low snow precipitation, which gave a deep frost down to 40–80 cm, whereas the two following winters had frost depths of 5–20 cm. During winter 1995–96, the two organic profiles close to the stream had a shallower frost depth than the mineral soil profile higher upslope, but a considerably larger amount of frozen water. The fraction of water that did not freeze despite several minus degrees in the soil was 5–7 vol.% in the mineral soil and 10–15 vol.% in the organic soil. From the measurements there were no signs of perched water tables during any of the three snowmelt periods, which would have been strong evidence for changed water flowpaths due to soil frost. When shallow soil layers became saturated during snowmelt, especially in 1997 and 1998, it was because of rising groundwater levels. Several rain on frozen ground events during spring 1996 resulted in little runoff, since most of the rain either froze in the soil or filled up the soil water storage. Copyright © 2001 John Wiley & Sons, Ltd.     

Recent snow cover changes over central European low mountain ranges

In this study, we simulated the snow water equivalent (SWE), rain-on-snow (ROS) events, evapotranspiration, and run-off for the period 1961–2016 in a central European region covered by low mountain ranges (<820 m a.s.l.) using a distributed hydrological model TRAnspiration and INterception evaporation model (TRAIN). We utilized improved cloud-free Moderate Resolution Imaging Spectroradiometer (MODIS) snow cover products to evaluate the modelled snow-covered area, indicating a good performance of the snow modelling. We analysed the intra- and inter-annual variations of the simulated hydrological variables and the synchronous climate variables (air temperature and precipitation). Trend detection indicates a significant SWE decline throughout the snow season, but principally at the high elevations; the most severe warming occurred in early spring (March), whereas precipitation showed a slight increase in January and February. The snowpack in February has displayed the most striking reduction during the past 56 years, which is likely related to both the highest susceptibility of snow to warming and the increased ROS occurrence in February since the early 1990s. The increased combination of high temperatures and extreme rainfalls, as well as the earlier snowmelt, has resulted in a run-off increase during the earlier winter but a decrease in March. The expected changing climate towards warmer and wetter winters will probably exacerbate winter flooding in the future.     

Effects of frozen soil and snow cover on cold‐season soil water dynamics in Tokachi,Japan

Despite the potential impact of winter soil water movements in cold regions, relatively few field studies have investigated cold‐season hydrological processes that occur before spring‐onset of snowmelt infiltration. The contribution of soil water fluxes in winter to the annual water balance was evaluated over 5 years of field observations at an agricultural field in Tokachi, Hokkaido, Japan. In two of the winters, soil frost reached a maximum depth of 0·2 m (‘frozen’ winters), whereas soil frost was mostly absent during the remaining three winters (‘unfrozen’ winters). Significant infiltration of winter snowmelt water, to a depth exceeding 1·0 m, occurred during both frozen and unfrozen winters. Such infiltration ranged between 126 and 255 mm, representing 28–51% of total annual soil water fluxes. During frozen winters, a substantial quantity of water (ca 40 mm) was drawn from deeper layers into the 0–0·2 m topsoil layer when this froze. Under such conditions, the progression and regression of the freezing front, regulated by the thickness of snow cover, controlled the quantity of soil water flux below the frozen layer. During unfrozen winters, 13–62 mm of water infiltrated to a depth of 0·2 m, before the spring snowmelt. These results indicate the importance of correctly evaluating winter soil water movement in cold regions. Copyright © 2010 John Wiley & Sons, Ltd.     

A laboratory investigation of the leaching of solute from snowpack by rainfall

Under controlled laboratory conditions, artificial rain leaches solute from snow columns, and gives rise to leachate with a composition similar to snowmelt, in addition to the solute initially present in the artificial rain. the initial concentration of ions in the leachate, normalized to the concentration of ions found in the original snow and corrected for the solute present in the artificial rain, is similar to those reported in other laboratory and field studies of snowmelt composition, but there is some evidence that the concentration of leached ions declines more rapidly than during snowmelt. Similarly, as in snowmelt studies, not all ions are leached with the same efficiency. Bearing in mind the confounding influences of snow crystal morphology and snow column hydrology, it seems likely that rain will leach solute from snowpack during rain-on-snow events, in a manner similar to leaching by snowmelt, and that the precise composition of the leachate will depend on the hydrological routing of rain-meltwater mixtures through the snowpack.     

Quantifying the role of the snowpack in generating water available for run‐off during rain‐on‐snow events from snow pillow records

Rain‐on‐snow events have generated major floods around the world, particularly in coastal, mountainous regions. Most previous studies focused on a limited number of major rain‐on‐snow events or were based primarily on model results, largely due to a lack of long‐term records from lysimeters or other instrumentation for quantifying event water balances. In this analysis, we used records from five automated snow pillow sites in south coastal British Columbia, Canada, to reconstruct event water balances for 286 rain‐on‐snow events over a 10‐year period. For large rain‐on‐snow events (event rainfall >40 mm), snowmelt enhanced the production of water available for run‐off (WAR) by approximately 25% over rainfall alone. For smaller events, a range of antecedent and meteorological factors influenced WAR generation, particularly the antecedent liquid water content of the snowpack. Most large events were associated with atmospheric rivers. Rainfall dominated WAR generation during autumn and winter events, whereas snowmelt dominated during spring and summer events. In the majority of events, the sensible heat of rain contributed less than 10% of the total energy consumed by snowmelt. This analysis illustrated the importance of understanding the amount of rainfall occurring at high elevations during rain‐on‐snow events in mountainous regions.     

Aspect control of water movement on hillslopes near the rain–snow transition of the Colorado Front Range

In the Colorado Front Range, forested catchments near the rain–snow transition are likely to experience changes in snowmelt delivery and subsurface water transport with climate warming and associated shifts in precipitation patterns. Snowpack dynamics are strongly affected by aspect: Lodgepole pine forested north‐facing slopes develop a seasonal snowpack, whereas Ponderosa pine‐dotted south‐facing slopes experience intermittent snow accumulation throughout winter and spring. We tested the degree to which these contrasting water input patterns cause different near‐surface hydrologic response on north‐facing and south‐facing hillslopes during the snowmelt period. During spring snowmelt, we applied lithium bromide (LiBr) tracer to instrumented plots along a north–south catchment transect. Bromide broke through immediately at 10‐ and 30‐cm depths on the north‐facing slope and was transported out of soil waters within 40 days. On the south‐facing slope, Br^? was transported to significant depths only during spring storms and remained above the detection limit throughout the study. Modelling of unsaturated zone hydrologic response using Hydrus‐1D corroborated these aspect‐driven differences in subsurface transport. Our multiple lines of evidence suggest that north‐facing slopes are dominated by connected flow through the soil matrix, whereas south‐facing slope soils experience brief periods of rapid vertical transport following snowmelt events and are drier overall than north‐facing slopes. These differences in hydrologic response were largely a function of energy‐driven differences in water supply, emphasizing the importance of aspect and climate forcing when considering contributions of water and solutes to streamflow in catchments near the snow line. Copyright © 2012 John Wiley & Sons, Ltd.     

Soil moisture states,lateral flow,and streamflow generation in a semi‐arid,snowmelt‐driven catchment

Hydraulic connectivity on hillslopes and the existence of preferred soil moisture states in a catchment have important controls on runoff generation. In this study we investigate the relationships between soil moisture patterns, lateral hillslope flow, and streamflow generation in a semi‐arid, snowmelt‐driven catchment. We identify five soil moisture conditions that occur during a year and present a conceptual model based on field studies and computer simulations of how streamflow is generated with respect to the soil moisture conditions. The five soil moisture conditions are (1) a summer dry period, (2) a transitional fall wetting period, (3) a winter wet, low‐flux period, (4) a spring wet, high‐flux period, and (5) a transitional late‐spring drying period. Transitions between the periods are driven by changes in the water balance between rain, snow, snowmelt and evapotranspiration. Low rates of water input to the soil during the winter allow dry soil regions to persist at the soil–bedrock interface, which act as barriers to lateral flow. Once the dry‐soil flow barriers are wetted, whole‐slope hydraulic connectivity is established, lateral flow can occur, and upland soils are in direct connection with the near‐stream soil moisture. This whole‐slope connectivity can alter near‐stream hydraulics and modify the delivery of water, pressure, and solutes to the stream. Copyright © 2005 John Wiley & Sons, Ltd.     

Characteristics of soil moisture in permafrost observed in East Siberian taiga with stable isotopes of water

Soil moisture and its isotopic composition were observed at Spasskaya Pad experimental forest near Yakutsk, Russia, during summer in 1998, 1999, and 2000. The amount of soil water (plus ice) was estimated from volumetric soil water content obtained with time domain reflectometry. Soil moisture and its δ¹⁸O showed large interannual variation depending on the amount of summer rainfall. The soil water δ¹⁸O decreased with soil moisture during a dry summer (1998), indicating that ice meltwater from a deeper soil layer was transported upward. On the other hand, during a wet summer (1999), the δ¹⁸O of soil water increased due to percolation of summer rain with high δ¹⁸O values. Infiltration after spring snowmelt can be traced down to 15 cm by the increase in the amount of soil water and decrease in the δ¹⁸O because of the low δ¹⁸O of deposited snow. About half of the snow water equivalent (about 50 mm) recharged the surface soil. The pulse of the snow meltwater was, however, less important than the amount of summer rainfall for intra‐annual variation of soil moisture. Excess water at the time just before soil freezing, which is controlled by the amount of summer rainfall, was stored as ice during winter. This water storage stabilizes the rate of evapotranspiration. Soil water stored in the upper part of the active layer (surface to about 120 cm) can be a water source for transpiration in the following summer. On the other hand, once water was stored in the lower part of the active layer (deeper than about 120 cm), it would not be used by plants in the following summer, because the lower part of the active layer thaws in late summer after the plant growing season is over. Copyright © 2002 John Wiley & Sons, Ltd.     

Rain on snow induced urban floods in cold maritime climate: Risk,indicators and trends

Urban floods pose a societal and economical risk. This study evaluated the risk and hydro-meteorological conditions that cause pluvial flooding in coastal cities in a cold climate. Twenty years of insurance claims data and up to 97 years of meteorological data were analysed for Reykjavík, Iceland (64.15°N; <100 m above sea level). One third of the city's wastewater collection system is combined, and pipe grades vary from 0.5% to 10%. Results highlight semi-intensive rain (<7 mm/h; ≤3 year return period) in conjunction with snow and frozen ground as the main cause for urban flood risk in a climate which undergoes frequent snow and frost cycles (avg. 13 and 19 per season, respectively). Floods in winter were more common, more severe and affected a greater number of neighbourhoods than during summer. High runoff volumes together with debris remobilized with high winds challenged the capacity of wastewater systems regardless of their age or type (combined vs. separate). The two key determinants for the number of insurance claims were antecedent frost depth and total precipitation volume per event. Two pluvial regimes were particularly problematic: long duration (13–25 h), late peaking rain on snow (RoS), where snowmelt enhanced the runoff intensity, elongated and connected independent rainfall into a singular, more voluminous (20–76 mm) event; shorter duration (7–9 h), more intensive precipitation that evolved from snow to rain. Closely timed RoS and cooling were believed to trigger frost formation. A positive trend was detected in the average seasonal snow depth and volume of rain and snowmelt during RoS events. More emphasis, therefore, needs to be placed on designing and operating urban drainage infrastructure with regard to RoS co-acting with frozen ground. Furthermore, more detailed, routine monitoring of snow and soil conditions is important to predict RoS flood events.     

Spatio‐temporal controls of snowmelt and runoff generation during rain‐on‐snow events in a mid‐latitude mountain catchment

A network of 30 standalone snow monitoring stations was used to investigate the snow cover distribution, snowmelt dynamics, and runoff generation during two rain‐on‐snow (ROS) events in a 40 km² montane catchment in the Black Forest region of southwestern Germany. A multiple linear regression analysis using elevation, aspect, and land cover as predictors for the snow water equivalent (SWE) distribution within the catchment was applied on an hourly basis for two significant ROS flood events that occurred in December 2012. The available snowmelt water, liquid precipitation, as well as the total retention storage of the snow cover were considered in order to estimate the amount of water potentially available for the runoff generation. The study provides a spatially and temporally distributed picture of how the two observed ROS floods developed in the catchment. It became evident that the retention capacity of the snow cover is a crucial mechanism during ROS. It took several hours before water was released from the snowpack during the first ROS event, while retention storage was exceeded within 1 h from the start of the second event. Elevation was the most important terrain feature. South‐facing terrain contributed more water for runoff than north‐facing slopes, and only slightly more runoff was generated at open compared to forested areas. The results highlight the importance of snowmelt together with liquid precipitation for the generation of flood runoff during ROS and the large temporal and spatial variability of the relevant processes. Copyright © 2015 John Wiley & Sons, Ltd.     

Recharge processes during snowmelt: An isotopic and hydrometric investigation

Results from hydrometric and isotopic investigations of unsaturated flow during snowmelt are presented for a hillslope underlain by well-sorted sands. Passage of melt and rainwater through the vadose zone was detected from temporal changes in soil water ²H concentrations obtained from sequential soil cores. Bypassing flow was indicated during the initial snowmelt phase, but was confined to the near-surface zone. Recharge below this zone was via translatory flow, as meltwater inputs displaced premelt soil water. Estimates of premelt water fluxes indicate that up to 19 per cent of the premelt soil water may have been immobile. Average water particle velocities during snowmelt ranged from 6.2 × 10^?7 to 1.1 × 10^?6 ms^?1, suggesting that direct groundwater recharge by meltwater during snowmelt was confined to areas where the premelt water table was within 1 m of the ground surface. Soil water ²H signatures showed a rapid response to isotopically-heavy rain-on-snow inputs late in the melt. In addition, spatial variations in soil moisture content at a given depth induced a pronounced lateral component to the predominantly vertical transport of water. Both factors may complicate isotopic profiles in the vadose zone, and should be considered when employing environmental isotopes to infer recharge processes during snowmelt.     

Snowmelt-generated runoff and soil erosion in Fife,Scotland

The hydrology and contrasting erosional responses of two snowmelt events on arable farmland in Fife, Scotland, are compared. Snowmelt-generated runoff in January 1993 caused widespread soil erosion across eastern Scotland. Gullying was exemplified by three sites in Fife, where thaw of a drifted snowpack was augmented by rainfall to produce a larger erosive response than meteorological data alone would have predicted. Up to 127 m³ of soil was lost from individual gullies in fields sown to winter cereals. In February 1996 snowfall of comparable depth again covered the field area, but a more uniform snowpack, slower thaw, greater crop cover and lower rainfall during the thaw phase combined to lessen the impact of erosion. These case studies demonstrate the complexity of the erosion/runoff relationship for rain on snow events, in which erosional severity depends not just on snow depth but on snow distribution, thaw rate and the amount and timing of rainfall during the thaw phase. © 1998 John Wiley & Sons, Ltd.     

MID-WINTER STEMFLOW DRAINAGE FROM BIGTOOTH ASPEN (POPULUS GRANDIDENTATA MICHX.) IN CENTRAL MASSACHUSETTS

Under winter conditions, stemflow drainage in forested ecosystems is often assumed to be a negligible component of the hydrological cycle. This paper reports on mid-winter stemflow drainage from the broadleaved deciduous tree species Populus grandidentata. Stemflow volumes from this species at air temperatures of < 0°C were found to be comparable to rainfall-generated stemflow during summer. Over the three-month period January–March 1993, stemflow ranged from 5.4 to 9.9% of the incident gross precipitation. Expressed as depth equivalents per unit trunk basal area, these stemflow inputs ranged from 1.8 to 4.9 m. These concentrated mid-winter inputs of liquid water to the bases of canopy trees were attributable to: (1) snow interception by the leafless woody frame of each tree; (2) snow retention by glazed ice precipitation associated with the snowfall event; (3) increased temperature at the bark/snow interface caused by the low albedo of the bark tissue; and (4) convergence of snowmelt drainage from steeply inclined upthrust primary branches. The hydrological and ecological significance of liquid water inputs to the forest floor under sub-zero conditions are discussed. © 1997 by John Wiley & Sons Ltd.     

Annual and seasonal fluctuations of precipitation and streamflow in the Aconcagua River basin, Chile

The El Niño-Southern Oscillation (ENSO) phenomenon has been shown to influence dramatically precipitation and streamflow in tropical western South America. The statistical properties of annual and winter precipitation totals and streamflow characteristics in the Aconcagua River basin, in temperate central Chile, are investigated in such a way as to permit the identification of flood- and drought-generating processes and their possible linkages to upset behavior in the tropical Pacific. Despite the considerable distance to those regions generally associated with ENSO events, the phenomenon produces marked effects upon the various physical processes which govern the surface hydrometeorology of the study area. El Niño years result in significant increases in annual and winter precipitation, particularly along the coastal margin. The likelihood of rain or rain-on-snow flooding, in the succeeding winter, increases, as does the size of spring snowmelt in the southern summer, 1 year after the upset conditions in the tropical region. Annual low flows are of higher magnitude and occur earlier in the year than is usual.     

Climate variability,snow, and physiographic controls on storm hydrographs in small forested basins,western Cascades,Oregon

Large floods are often attributed to the melting of snow during a rain event. This study tested how climate variability, snowpack presence, and basin physiography were related to storm hydrograph shape in three small (<1 km²) basins with old‐growth forest in western Oregon. Relationships between hydrograph characteristics and precipitation were tested for approximately 800 storms over a nearly 30‐year period. Analyses controlled for (1) snowpack presence/absence, (2) antecedent soil moisture, and (3) hillslope length and gradient. For small storms (<150 mm precipitation), controlling for precipitation, the presence of a snowpack on near‐saturated soil increased the threshold of precipitation before hydrograph rise, extended the start lag, centroid lag, and duration of storm hydrographs, and increased the peak discharge. The presence of a snowpack on near‐saturated soil sped up and steepened storm hydrographs in a basin with short steep slopes, but delayed storm hydrographs in basins with longer or more gentle slopes. Hydrographs of the largest events, which were extreme regional rain and rain‐on‐snow floods, were not sensitive to landform characteristics or snowpack presence/absence. Although the presence of a snowpack did not increase peak discharge in small, forested basins during large storms, it had contrasting effects on storm timing in small basins, potentially synchronizing small basin contributions to the larger basin hydrograph during large rain‐on‐snow events. By altering the relative timing of hydrographs, snowpack melting could produce extreme floods from precipitation events whose size is not extreme. Further work is needed to examine effects of canopy openings, snowpack, and climate warming on extreme rain‐on‐snow floods at the large basin scale. Copyright © 2008 John Wiley & Sons, Ltd.     

Soil C and N response to changes in winter precipitation in a subalpine forest ecosystem,NW Italy

Among the potential effects of climate change on subalpine forest ecosystems during the winter season, the shift in snowline towards higher altitudes and the increase in frequency of rain events on the snowpack are of particular interest. Here, we present the results of a 2‐year field experiment conducted in a forest stand (Larix decidua) in NW Italy at 2020 m a.s.l. From 2009 to 2011, we monitored soil physical characteristics (temperature and moisture), and soil and soil solution chemistry, in particular carbon (C) and nitrogen (N) forms and their change in time, as affected by simulated late snowpack accumulation and rain on snow events. Late snowpack accumulation determined a stronger effect on soil thermal and moisture regimes than rain on snow events. Also soil chemistry was significantly affected by late snowfall simulation. Although microbial biomass C and N were not reduced by soil freezing, soil contents of the more labile dissolved organic carbon and inorganic N increased when the soil was affected by mild/hard freezing. Variations in the soil solution were shifted with respect to those observed in soil, with an increase in N‐NO₃^? concentrations occurring during spring and summer. This study highlights the potential N loss in subalpine soils under changing environmental conditions driven by a changing climate. Copyright © 2013 John Wiley & Sons, Ltd.