This is a frightening map, especially given the fact that this is normally near the peak in snowpack across the West. There are many far-reaching consequences from this historic snow drought, ranging from increasing risk of summer wildfires to major water concerns.
The Canadian west is anomolous.
Near average overall but above average further north, well below in the south, which applies the major rivers to populated areas.
I particularly follow this because in 1981, my first ever IT job was in adapting the US Army's river modeling and flood forecasting programs for the Alberta government. Mainframe Fortran.
One of the main inputs was detailed snowpack data.
https://ca.news.yahoo.com/b-c-snowpack-reveals-sharp-165713791.html
Zack Labe
Eric Lawton