Happy New (water) Year!
Updated: Apr 26, 2020
The 2019 water year is off to a great start! Two days into the new water year, moisture from Hurricane Rosa streamed into the Southern San Juan Mountains resurrecting the San Juan River from near record low flow. The steady rain generated more than a 10x increase in streamflow in the San Juan River last week. And a decent moisture supply has continued to drift our way. The best news is the high mountains are already blanketed under a layer of foreign-looking snow!
October 1st is the official start of the new year for hydrologic record keeping because precipitation usually switches over to snow, and that snow is stored in the high country feeding spring runoff the following calendar year.
Since we've started a new water year, we can get closure on the dismal 2018 water year. Both 2018 streamflow and precipitation nearly set record lows. The San Juan River ended up dropping below the 2002 level in September reaching a low of 8.4 cfs on September 19th (provisional data).
The Upper San Juan SNOTEL site recorded 25.5 inches of precipitation, which is 48% of the 1981-2010 average of 53 inches. 2018 finished with 1.2 inches more precipitation than 2002, which had a total of 24.3 inches.
Fortunately, the 2018 water year is behind us and 2019 is off to a great start, but whether the wet weather will continue is up in the air. However, a few years ago, my global science class used October snowfall to predict how the rest of the snow season would end up . More on that later. In the meantime, we can enjoy an iconic autumn: snow capped peaks looming high above stands of blazing aspen.