2017-2018 Winter Storm Reports- December Recap from CSAS
2017-2018 Winter Storm Reports
Non-Storm Report #3: December Recap, January 2, 2018
Greetings from Silverton,
December 2017 is now behind us and we are still waiting for winter to begin in most of the Colorado high country. Colorado (AZ, NM, and UT) experienced their warmest November on record and one of the driest for many SNOTEL stations around Colorado. December continued the trend of being exceptionally warm – particular in the mountains – and exceptionally dry. Many meteorological stations rank November and December as one of their driest on record.
Here at Senator Beck Basin in the San Juan Mountains, October was the 4th warmest and the warmest November and December in our POR. It was the 4th driest October, and driest November and December, by far, in our POR. The folks at Telluride ski resort haven’t seen a drier December in 34 years.
Currently, SWE at Swamp Angel (elevation 11,060’) is 2.8” (71 mm), nearby Red Mt. SNOTEL is showing 3.6” (91 mm). Cumulative precipitation since October 1st at SASP is 3.2” (82 mm), and at Red Mt. SNOTEL the same story with 3.3” (84 mm). Average January 1st cumulative precipitation at SASP and Red Mt. is 12.9” (327 mm) and 12” (307 mm), respectively. You might have noticed, but we have yet to issue a Storm Report so far this season since our criteria has not been met – a precipitation event that brings at least 12 mm of precipitation with no gap between measured precipitation greater than 12 hours. Usually by January 1st we have already issued ~9 Storm Reports.
So far this season we have not documented a dust event or observed dust-on-snow, where snow exists, in the San Juan Mountains. Assuming we eventually get the snow to melt and unless conditions change across the southwest, the set-up going into the height of dust season (March/April/May) doesn’t look good. The folks at NIDIS and Colorado Climate Center have much of Colorado designated as abnormally dry and much of western Colorado classified as moderate drought. The southern Colorado plateau, our primary dust source, is in moderate drought with a good portion of southern Utah in severe drought. See drought monitor depiction below. Reduced soil moisture as well as stressed and reduced vegetation make soils vulnerable to wind erosion and transport to the Colorado mountains. Last year, for example, the desert southwest was very wet most of the winter season and consequently we documented only 4 dust events with 2 of those events being very light.
Looking ahead: The forecast is calling for much of the same for the remainder of this week, mainly dry and mild with temperatures staying several degrees above normal due to an upper level ridge maintaining a dry northwest flow. But…..fingers crossed, there is potential for unsettled weather starting later Saturday into Sunday. Models are digesting a trough pattern over the eastern Pacific with a moderate amount of precipitation potential.
Andrew doing his best to stay positive with this grim winter do date-Swamp Angel on 1/1/18
Review this report and all 2017-18 Monthly Reports HERE