[1/n] Non-COVID thread: upcoming #snow melt in central #BritishColumbia. The recent snow survey and water supply forecast from the River Forecast Centre (who aren't on Twitter?) showed big snowpacks in the upper Fraser Basin. https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/river-forecast/2020_apr1.pdf

[2/n] but I wanted to dig into some of the individual station data and look at (a) how much snow there is relative to normal, and (b) rates of snowpack depletion relative to normal. Once melt begins, it tends to go quickly. So are the high elevation snowpacks there yet?

[3/n] from a forecasting perspective, its not the depth of snow that's important: it's the depth of water if all the snow was melted, AKA the 'snow water equivalent'

[4/n] I am using data compiled by the fine folks at the BC government, who make all this data accessible.

Current year SWE (hourly): http://www.env.gov.bc.ca/wsd/data_searches/snow/asws/data/SW.csv

Historical SWE (daily): https://pub.data.gov.bc.ca/datasets/5e7acd31-b242-4f09-8a64-000af872d68f/daily_asp_archive.csv

[5/n] after some wrangling to get average daily SWE for the current year, and mean daily SWE for the period of record from the historical data, we can start to look at (a) current daily SWE and (b) rates of SWE change versus the historical record. Some results:

[6/n] Big snowpacks in the upper Fraser! Here is Revolution Creek. Way above normal snowpack. And no sign yet of turning the corner (decreases in SWE every day), but based on the historical data it should be happening any day.

[7/n] Disclaimer: the data have not been checked (yet)! There are some features in the long-term average SWE that lead to the large average rates of change at this site, and some others. But here's another site with a big snowpack that looks like its started to turn:

[8/n] One more site in the upper Fraser (east of Prince George): Dome Mountain. Not expecting the turn for another few weeks, but another snowpack well above normal.

[9/n] And where the heck are these sites located? Roughly here:

[10/10] final comment: DOY (on the x-axis of all the plots) is day of year, i.e. 1 Jan is DOY 1. Coding in #Python, and the data are courtesy @govbc and the agencies that maintain these important snowpack observations.