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NIDIS Intermountain West
Drought Early Warning System
February 20, 2018


Current U.S. Drought Monitor Depiction


Recommended Changes

Summary: February 20, 2018

Last week the Upper Colorado River Basin saw a mix of precipitation.  The higher elevations in western Colorado and central Utah received widespread amounts between 0.50 inches up to 2.00 inches.  Some isolated areas in the highest elevations of the San Juan Mountains along the Divide received up to 4.00 inches.  This may have been the best week in the San Juans this season, however, this is near average for this time of the season and deficits are still quite high.  Elsewhere in the UCRB, mainly the lower elevations, precipitation amounts were below 0.50 inches.  Southwest Colorado remained drier than average for this time of year.  Continuing the pattern of below normal precipitation.

Eastern Colorado was mostly dry this week, with much of the area receiving less than 0.10 inches of new precipitation.  The Front Range from Larimer County to El Paso County saw a nice snow storm Sunday evening through Monday, dropping between 0.10 inches to 0.5 inches of liquid, the highest amounts were in Boulder County.

Despite the bump in precipitation, Water Year Precipitation Percentiles from SNOTEL sites in southern and western Colorado and Utah remain in the single digits, with most below the 5th percentile.  Snowpack did see an increase the last week, however it was a near normal increase for this time in the season.  The percent of normal for some basins did increase, but remain much below normal.

Temperatures through the UCRB and Intermountain West region, with the exception of northern Wyoming, were at least 3 degrees above normal.  Southeastern Colorado saw temperatures 6 to 9 degrees warmer than normal.  Obviously, this did not help conditions.

The precipitation in the higher elevations will help hold off any degradations this week, but it wasn't enough to improve conditions.  Since the lower elevations in southwest Colorado missed the best precipitation, and what did fall is not going to help, D3 is warranted. 

Recommendations

UCRB:  We are recommending introducing D3 in southwest Colorado and into southeast Utah and northwest New Mexico.  This area is seeing very low SPIs (-1.5 to -2 and below) on the 90-day out to the start of the water year and going out 6 and 9 months.  SNOTEL snowpack and precipitation percentiles are in the single digits for this area, some of the lowest years on record going back 30+ years and numerous sites.  Due to the prolonged dryness and high temperatures, the winter wheat crop in southwest Colorado has failed and soils are drying out.  What little precipitation has fallen has not helped.  Ag impacts this season should be limited to dryland and rangeland.  Since this drought is following a few good years, water supply is in good shape and irrigation water should be in full supply. 

Some of our on the ground reports suggest D3 is imminent, but it might be a little bit soon to go for it.  The Colorado Climate Center feels D3 is justified based on the data and low snowpack. 

Eastern Colorado: Status quo.  

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