Spring rain-on-snow

First major rain-on-snow event of the season. Stage = 95cm, water temp. = 5.3C.

Warm temperatures up to 11.6 C and intense rain showers (3.5 mm/h) through the night and during the morning of the 19th led to typical rain-on-snow conditions and a moderately high discharge in Takiya River (stage about 1m).

Two students and I completed a snow survey of three locations (deciduous larch, mature cedar, and open paddy field). The snow pack beneath the mature cedar remained much firmer and more icy compared to the other two sites, which can be explained by the different energy balance between sites. During such rain-on-snow events we would expect the net radiation balance and the energy brought by warm winds to be greater in the open and deciduous larch sites.

The larch site had the highest snow water equivalent (SWE) and the greatest snow depth. The paddy and mature cedar site had similar SWE, but the depth was less and the density higher in the paddy where liquid water content was particularly high at the base of the snow pack.

Snow depths (cm)
Paddy: 52
Cedar: 72
Larch: 88

Snow survey in the larch site