Low snow year

This winter has been a low snow year for the Niigata region. Temperatures appear to have been about average, so the reason for the lack of snow seems to be below-average precipitation levels. Possibly there was also a tendency for precipitation days to have been relatively warm, producing more rain and less snow, but I have yet to analyze the data to confirm this. Now the snowmelt season is here already.

Larch lysimeter site, snow depth = 55-60cm

Today we completed a snow survey which showed that the snowpack was similar in size to the last survey in late January. Normally the snowpack would grow substantially through February and into March, but this year it remained marginal all through the winter in the low elevations. The snow lysimeter data showed that the snowpack had entered the spring snowmelt season with a daily snowmelt runoff pattern commencing in mid-March.

Cedar lysimeter site, snow depth = 25-30cm

Young cedar site, snow depth = 30-80cm

Mountain snow survey

Approaching the summit through beech forests

Today our party had to work hard to climb up to a peak at 610m elevation to do snow survey. Initially we climbed up through cedar plantation, then we emerged into the deciduous forests of the upper mountain slopes covered by oak and then beech. Our objective is to measure the snowpack at high elevation during late winter to early spring when the snowpack amount reaches a maximum for the season.

View of the upper reaches of the Takiya River Basin from 610m elevation

This data is extremely valuable for use in calibrating snow models for the Takiya River Basin. A regular snow survey was conducted as well as a snow pit sampling analysis which gives the changes in snow density at 10cm intervals from the snow surface down to the base of the snowpack. As much as possible, we also monitor air temperature in the high elevations by attaching temperature loggers to trees at the 610m peak.

Summit of the 610m peak - our survey point for today

At the summit, snow depths ranged from 152 to 191cm, with snow densities of 0.42 compared to water. Therefore the snow water equivalent (SWE) was between 64 and 80cm. Three years ago in 2011 we had a relatively heavy snow year with an average snow depth of 240cm and SWE of 106cm at the same point, so we can see that this year is a relatively light snow year. Still it is hard work to dig out the snow pit in even 170cm depth of snow!