March in the West
March saw a return to active weather following a warmer and drier than normal February in much of the West. Several strong storms impacted the region, boosting snowpack across most western mountains. As has been the general pattern this cool season, drier than normal conditions dominated over the southern tier of the region with wetter conditions in the Northwest, in contrast with the expectations of strong El Niño events.
Near to well-above normal temperatures were observed across the West. Some of the greatest temperature anomalies occurred in central and eastern Montana, typical of a strong El Niño event and similar to preceding winter months. Miles City and Glasgow both had their 4th warmest March on record at 42.6 F (5.9 C), 7.9 F (4.4 C) above normal, and 39.8 F (4.3 C), 8.1 F (4.5 C) above normal, respectively. Records for Miles City began in 1937 and Glasgow in 1948. In the Great Basin, temperatures at Elko, Nevada, averaged to 42.9 F (6 C), 4 F (2.2 C) above normal and 8th warmest in a 127-year record. Farther south, March average temperature in Tucson, Arizona was 65 F (18.3 C), 4.9 F (2.7 C) above average, and tied for 4th warmest from 1946-present.
Well above normal precipitation was observed in the Pacific Northwest, northern California, and central Rockies this month and helped to alleviate drought conditions in a large swath from northern California to western Montana. In central Washington, Wenatchee observed March precipitation totaling 2.29 in (58 mm), 357% of normal and the second wettest in a 58-year record. Northern California received beneficial precipitation as well; Arcata logged 10.48 in (266 mm) this month, 166% of normal and the 4th wettest March since records began in 1945. Following a relatively dry winter and expanding drought conditions, western Wyoming received above normal precipitation. Riverton recorded 2.7 in (69 mm) precipitation, 387% of normal, the 2nd wettest March since records began in 1907. Much of this fell as snow, setting the record for snowiest March at Riverton at 22.1 in (56 cm). Snowpack received a boost across the Sierra Nevada, Cascades, northern and central Rockies, and other ranges across the Northwest, with all but a handful of basins ending the month above normal. Basins south of 40° N did not fare as well. Sierra Nevada snowpack averaged to 86% of normal at month’s end. The southern Rockies were generally <75% of normal, and snowpack across Arizona and New Mexico was <35% of normal, or in many cases non-existent.
Dry conditions seen in February persisted across the Southwest this month. No measurable March precipitation was recorded in Albuquerque, New Mexico, or Las Vegas, Nevada. A dry March was observed in Albuquerque 12 other years since 1897, in Phoenix 10 other years since 1933, and in Las Vegas, 16 other years since records began in 1948. Phoenix recorded its 3rd rain-free February/March in 120 years, unusual during a strong El Nino. Southern California was also much drier than normal; San Diego received only 0.76 in (19 mm) of rain, 41% of normal.
As during the past two months, March temperatures were above normal throughout Alaska. Average temperature at Fairbanks was 19.8 F (-6.8 C), 8.4 F (4.6 C) above normal and the 6th warmest since records began in 1929. Precipitation was below normal across much of the state, though above normal in the South central region. Anchorage received 1.23 in (31 mm), 205% of normal. Further south, dry conditions associated with El Niño persisted through March in Hawaii. Most stations in the state reported below normal precipitation, including Honolulu, which received only 0.22 in (6 mm), 11% of normal. Drought conditions worsened this month for parts of Big Island, Lanai, Oahu, Kauai and Molokai.
Significant Events for March 2016
March 13: Strong wind storm impacts western Washington: Winds in excess of 50 mph (80 kph) knocked down trees and power lines, caused damage to and closure of major roads, and resulted in one death due to a falling tree. Approximately 250,000 people were without power at the height of the storm.
March 11: Flooding and mudslides in northern California: Mudslides associated with heavy rainfall occurred on Highway 1 north of Ft. Bragg, trapping a Caltrans driver responding to a previous slide. Minor flooding and road closures/poor road conditions closed schools in the northern San Francisco Bay Area.
March 28: Great Basin snowstorm: Heavy snow associated with a cold “inside slider” storm system caused >30 automobile crashes, school and road closures in Reno NV, where some areas received over 10 in (25 cm) of snow. The Reno airport total of 6.8” (17 cm) tied for the 3rd latest snowfall this large since 1937. Heavy snow also impacted central and eastern NV and southern Idaho, impeding travel.
March (all month): California water resources show improvement, though drought persists: On March 13, California’s largest reservoir, Lake Shasta, reached its historical average storage for the first time since 2013. On March 21st, the northern California 8-Station Index reached 50.3 inches (1278 mm) for the water year (Oct 1) to-date, the first time since 2011 that the index has been above the water year average of 50 in (1270 mm).