The 2019 Winter Review and Spring Runoff Prediction
Updated: Apr 26, 2020
The 2019 winter was officially a winner! The most encouraging sight was seeing the drinking water reservoirs cascading over their spillways! The low elevation snow-melt topped off all of the uptown reservoirs, which is pretty incredible considering that Lake Hatcher was 9 feet down, and Steven's Reservoir was 14 feet down last fall!
After a fabulous February at the Upper San Juan SNOTEL site (12.5 inches of water), March matched the moisture and raised it (13.9 inches of water)!
The March 2019 net change in snow water equivalent at the Upper San Juan SNOTEL site tied 1975 as the 4th highest over the last 81 years (only 1961, 1985, and 1938 were higher).
The snow water equivalent at the Upper San Juan site usually peaks on April 15th, which is exactly when we peaked this year with 41.7 inches of water (129% or 9.4 inches of water above normal). Since then, we've lost 5.2 inches of water, but we're still 121% above normal.
The 2019 snow water equivalent peak (41.7 in) ranks 3rd during the last 20 years behind 2005 (53.8 in) and 2008 (47.8 in). The 2019 winter started out slowly, but brought 2.7 times more water than 2018!
We did set one snow record: the 2019 maximum snow depth at the Wolf Creek Pass Summit SNOTEL site reached 153 inches topping 2005 and 2008! The snowpack during those monster years must have settled more due to higher moisture content. The only place in the lower 48 that had more snow on the ground was the Sierra Nevada Range (>200 in).
The San Juan River is currently running above average and already reached 1660 cfs on 4/20, which eclipsed the measly 2018 peak (1330 cfs on May 10th).
Every year I enjoy trying to predict the magnitude and timing of the peak spring runoff. My Snowflow Model is predicting 3440 cfs on May 29th. The historic median is 2465 cfs on May 26th. However, anything is possible during springtime in the Rockies!