An investigation on the development of liquid water content in different snow types during slushflow-inducing weather conditions
Master thesis
Permanent lenke
https://hdl.handle.net/11250/3148717Utgivelsesdato
2024-06-03Metadata
Vis full innførselSamlinger
- Master theses [112]
Sammendrag
Slushflows, defined as rapid mass-movements of water-saturated snow, occur when high liquid watercontent (LWC) causes bonds to melt and the snowpack to lose cohesion, triggering flow. Characterized bytheir shallow release angles and the potential for extensive runouts, slushflows typically occur during rain-on-snow events or due to significant melting. The presence of an impermeable layer beneath or within thesnowpack is normally required for water to accumulate.
An important consideration for the improvement of slushflow prediction is understanding the role snowtype has on the development of LWC in the snowpack. To assess this, LWC was measured in snowprofiles before and during weather events conducive to slushflow occurrence, using an SLF Snow Sensor.In addition, the SLF sensor was evaluated as a tool to measure LWC and compared with the traditionalhand wetness test.
Results indicate that the formation of preferential flow is important for water transport in snow. Whileprecipitation particles and decomposing, fragmented particles may facilitate preferential flow, ripe meltforms tend to promote matrix flow. Thick ice layers can impede vertical water movement and redirect itlaterally. Volume and rate of water supply may be as important as grain form in determining the mode offlow.
Comparisons between LWC estimated using the hand wetness test and values from the SLF Snow Sensoralign with existing literature, attesting to the efficacy of the hand wetness test as a qualitative method forassessing LWC, especially for internal comparison. When precise values are required, the hand wetnesstest is insufficient, and use of the SLF Snow Sensor is more suitable. The requirement for an externaldensity measurement to calculate LWC significantly increases the workload.