January in the West
Temperatures were mostly above normal throughout the west except for portions of the Southwest and a few intermountain valley locations that were mired in cold air from strong inversions. The Pacific Northwest was particularly mild. Spokane, WA, had their 5th warmest January in 120 years while in Lewiston, ID, it was the 4th warmest January on record. Lewiston reported only 6 days with minimum temperatures below freezing. Contrast that with Death Valley, CA, which reported 5 days of freezing temperatures and an average monthly minimum temperature only 3 degrees F (1.7 C) warmer than Lewiston. Conversely, the average temperature at Moab Airport, UT, was one of the coldest in the west at 14.6 F (-9.7 C) beating out most locations in Montana and Wyoming. Grand Junction, CO, had its coldest January in 18 years.
Precipitation was well above normal in the southwest but extremely dry in most of Wyoming and eastern Colorado. The Pacific Northwest was near to slightly above normal for the month. In a strange turn of events, Yuma, AZ, reported 2 ½ times as much rain as Hilo, HI, for the month. Yuma’s total of 2.44 inches (62 mm) was their 2nd greatest January total ever, narrowly missing the record of 2.49 (63 mm) set in 1949. Their daily total of 1.95 (50 mm) inches on the 21st was the greatest one-day January total ever. Las Vegas, NV, recorded their 5th wettest January on record dating back 115 years.
Mountain snowpack increased significantly in the Sierra Nevada of California, going from 75% of normal early in the month to 100% by the end. In Arizona, mountain snowpack ranged anywhere from 185% to 300% of normal by month’s end. The rest of the west (except southern Utah, southwest Colorado, and New Mexico) was below to well below normal (60% to 90%) by the end of January.
Significant Events for January 2010
January 16-23: Powerful storms in California and the Southwest: A series of strong storms hit the Southwest causing extensive damage and flooding throughout the region. The storm track was generally from northern California to southern California, across southern Nevada, Utah, and Colorado and most of Arizona and New Mexico. Rainfall totals exceeded 20 inches (508 mm) in the higher elevations of California for the week while snowfall totals were in excess of 90 inches (229 cm) around Mammoth Lakes, CA. Strong winds of up to 90 mph downed trees and led to the death of two people when trees fell on their homes. Over 23,000 customers in southern California were without power for a short time on the 18th while customers in Siskiyou County to the north were without power for up to 30 hours on the 20th from heavy, wet snow downing trees and power lines. Numerous debris flows occurred where heavy rain fell on the burned areas of southern California leading to evacuations for nearly 500 homes in the cities of La Canada and Flintridge on the 19th to the 20th. In Arizona, 50.7 inches (129 cm) of snow fell in Flagstaff for the third highest five-day total ever there. One child was swept to his death in Yavapai County when the family attempted to cross a flooded road. Near Wikieup, AZ, the Big Sandy River crested at 17.9 feet, washing away numerous roads and setting a new all-time record crest, breaking the previous record of 16.4 feet set back in March 1978. In Durango, CO, snow and debris were up to 12 feet deep closing local roads and highways.
January 2010 Departure from Normal Temperature and Percent of Normal Precipitation for Western United States