Spring Runoff 2019: Let's Call It a Come-back!
Updated: Jun 13, 2019
The town of Pagosa Springs can breathe a sigh of relief: it appears that the much-anticipated peak spring runoff event has occurred without causing too much damage.
The USGS gauging station (located below the hot springs bike bridge) recorded a preliminary peak flow of 4340 cfs on 6/9/19 at 2 AM, which was one day later and 340 cfs higher than my revised prediction. 4340 cfs is 3.3 times higher and a month later than last year's peak (1330 cfs on 5/10/18) and 1.8 times higher than the 83-year median (2470 cfs on 5/26). And plenty of snow remains to generate above-normal flows for the rest of the month, but I don't think the river will reach 4,000 cfs for the rest of the season thanks to the mild high temperatures.
Currently, the Upper San Juan SNOTEL site has 12.9 inches of water stored in the remaining 27-inch snowpack. The site lost 11.5 inches of water over the last week and 2 inches of water melted out of the snowpack on 6/8 to generate the peak flow. Normally the Upper San Juan site loses about an inch of water per day (but that's usually in late May instead of June). The Wolf Creek Summit SNOTEL site still has 28.9 inches of water locked up in the 57-inch base! This site lost 10.5 inches of water over the last week and 1.9 inches on 6/8. Even though the Wolf Creek site has tons of snow, it's located at 11,000 feet, which is not representative of the majority of the San Juan River watershed (the bulk of the 281 square-mile watershed has much less if any snow).
The 2019 peak runoff is the 5th highest spring flow event in the last 40 years and the highest since 2005. Fortunately, the river didn't reach 5,000 cfs like it did in 1979 and 1995. More significant flood damage happens at that threshold and a lower flow means a longer rafting season (sorry anglers).
Over the past 40 years, the 2019 snowpack is 2nd only to 1995 in terms of lasting the longest. The Upper San Juan SNOTEL site is usually out of snow by June 1st and it appears like the snow will last another week.
Ironically, last year I was trying to find years that were as bad as 2018, and this year I'm sorting through the records to find years that are as good as this one! On this date last year, the San Juan River was running at 150 cfs and this year we're boasting over 3000 cfs!
Instead of clinging to rafts through rapids, people were floating the lazy river on tubes. This week, I had to re-route my run around the flooded sections of the river trail, and there is barely enough clearance for rafts to pass under the Malt Shop bridge! It's been quite the come-back!