Influence of Initial Snowpack Properties on Runoff Formation during Rain-on-Snow Events

Würzer, Sebastian; Jonas, Tobias; Wever, Nander; Lehning, Michael

doi:10.1175/jhm-d-15-0181.1

Cited by 90 publications

(115 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The setup of the SNOWPACK model is similar to the setup used for simulations in Würzer et al (2016). For all simulations, snow depth was constrained to observed values, which means that the model interprets an increase in observed snow depth at the stations as snowfall (Lehning et al, 1999;Wever et al, 2015).…”

Section: Snowpack Model Setupmentioning

confidence: 99%

Modelling liquid water transport in snow under rain-on-snow conditions – considering preferential flow

Würzer

Wever

Juras

et al. 2017

Hydrol. Earth Syst. Sci.

Self Cite

View full text Add to dashboard Cite

Abstract. Rain on snow (ROS) has the potential to generate severe floods. Thus, precisely predicting the effect of an approaching ROS event on runoff formation is very important. Data analyses from past ROS events have shown that a snowpack experiencing ROS can either release runoff immediately or delay it considerably. This delay is a result of refreeze of liquid water and water transport, which in turn is dependent on snow grain properties but also on the presence of structures such as ice layers or capillary barriers. During sprinkling experiments, preferential flow was found to be a process that critically impacted the timing of snowpack runoff. However, current one-dimensional operational snowpack models are not capable of addressing this phenomenon. For this study, the detailed physics-based snowpack model SNOWPACK is extended with a water transport scheme accounting for preferential flow. The implemented Richards equation solver is modified using a dual-domain approach to simulate water transport under preferential flow conditions. To validate the presented approach, we used an extensive dataset of over 100 ROS events from several locations in the European Alps, comprising meteorological and snowpack measurements as well as snow lysimeter runoff data. The model was tested under a variety of initial snowpack conditions, including cold, ripe, stratified and homogeneous snow. Results show that the model accounting for preferential flow demonstrated an improved overall performance, where in particular the onset of snowpack runoff was captured better. While the improvements were ambiguous for experiments on isothermal wet snow, they were pronounced for experiments on cold snowpacks, where field experiments found preferential flow to be especially prevalent.

show abstract

Section: Snowpack Model Setupmentioning

confidence: 99%

Modelling liquid water transport in snow under rain-on-snow conditions – considering preferential flow

Würzer

Wever

Juras

et al. 2017

Hydrol. Earth Syst. Sci.

Self Cite

View full text Add to dashboard Cite

show abstract

“…An enhanced version of the rainfall simulator described in Juras et al (2013Juras et al ( , 2016 was designed to achieve rain intensities close to observations during natural ROS events (Osterhuber, 1999;Rössler et al, 2014;Würzer et al, 2016). The new device was equipped by a Lechler 460.368.30.CA nozzle which was precisely calibrated in the laboratory and again on site.…”

Section: Rainfall Simulation and Monitoringmentioning

confidence: 99%

Rainwater propagation through snowpack during rain-on-snow sprinkling experiments under different snow conditions

Juras

Würzer²,

Pavlásek

et al. 2017

Hydrol. Earth Syst. Sci.

Self Cite

View full text Add to dashboard Cite

Abstract. The mechanisms of rainwater propagation and runoff generation during rain-on-snow (ROS) events are still insufficiently known. Understanding storage and transport of liquid water in natural snowpacks is crucial, especially for forecasting of natural hazards such as floods and wet snow avalanches. In this study, propagation of rainwater through snow was investigated by sprinkling experiments with deuterium-enriched water and applying an alternative hydrograph separation technique on samples collected from the snowpack runoff. This allowed us to quantify the contribution of rainwater, snowmelt and initial liquid water released from the snowpack. Four field experiments were carried out during winter 2015 in the vicinity of Davos, Switzerland. Blocks of natural snow were isolated from the surrounding snowpack to inhibit lateral exchange of water and were exposed to artificial rainfall using deuterium-enriched water. The experiments were composed of four 30 min periods of sprinkling, separated by three 30 min breaks. The snowpack runoff was continuously gauged and sampled periodically for the deuterium signature. At the onset of each experiment antecedent liquid water was first pushed out by the sprinkling water. Hydrographs showed four pronounced peaks corresponding to the four sprinkling bursts. The contribution of rainwater to snowpack runoff consistently increased over the course of the experiment but never exceeded 86 %. An experiment conducted on a non-ripe snowpack suggested the development of preferential flow paths that allowed rainwater to efficiently propagate through the snowpack limiting the time for mass exchange processes to take effect. In contrast, experiments conducted on ripe isothermal snowpack showed a slower response behaviour and resulted in a total runoff volume which consisted of less than 50 % of the rain input.

show abstract

“…Liquid water in snow rules runoff timing and amount (Lehning et al, 2006;Wever et al, 2014;Würzer et al, 2016), snowpack mechanical properties and stability in wet conditions (Marshall et al, 1999;Baggi and Schweizer, 2008;Mitterer et al, 2011Schmid et al, 2015), and snow albedo (Dietz et al, 2012). Furthermore, Harper et al (2012), Forster et al (2014), and Machguth et al (2016) report that meltwater percolation-storage dynamics in snow and firn might play an important role in determining the timing of sea-level rise by climate change.…”

Section: Introductionmentioning

confidence: 99%

Observations of capillary barriers and preferential flow in layered snow during cold laboratory experiments

et al. 2016

View full text Add to dashboard Cite

Abstract. Data of liquid water flow around a capillary barrier in snow are still limited. To gain insight into this process, we carried out observations of dyed water infiltration in layered snow at 0 • C during cold laboratory experiments. We considered three different finer-over-coarser textures and three different water input rates. By means of visual inspection, horizontal sectioning, and measurements of liquid water content (LWC), capillary barriers and associated preferential flow were characterized. The flow dynamics of each sample were also simulated solving the Richards equation within the 1-D multi-layer physically based snow cover model SNOW-PACK. Results revealed that capillary barriers and preferential flow are relevant processes ruling the speed of water infiltration in stratified snow. Both are marked by a high degree of spatial variability at centimeter scale and complex 3-D patterns. During unsteady percolation of water, observed peaks in bulk volumetric LWC at the interface reached ∼ 33-36 vol % when the upper layer was composed by fine snow (grain size smaller than 0.5 mm). However, LWC might locally be greater due to the observed heterogeneity in the process. Spatial variability in water transmission increases with grain size, whereas we did not observe a systematic dependency on water input rate for samples containing fine snow. The comparison between observed and simulated LWC profiles revealed that the implementation of the Richards equation reproduces the existence of a capillary barrier for all observed cases and yields a good agreement with observed peaks in LWC at the interface between layers.

show abstract

Influence of Initial Snowpack Properties on Runoff Formation during Rain-on-Snow Events

Cited by 90 publications

References 48 publications

Modelling liquid water transport in snow under rain-on-snow conditions – considering preferential flow

Modelling liquid water transport in snow under rain-on-snow conditions – considering preferential flow

Rainwater propagation through snowpack during rain-on-snow sprinkling experiments under different snow conditions

Observations of capillary barriers and preferential flow in layered snow during cold laboratory experiments

Contact Info

Product

Resources

About