March in the West
March was the 4th consecutive month of widespread above normal temperatures in the West. Precipitation was below normal for a majority of the West, though scattered areas of the Desert Southwest and along the northern tier of the region received above normal precipitation.
Anomalously strong and persistent high pressure anchored over the West this month resulted in record and near-record March temperatures throughout the region. Greatest departures from normal were observed in California, the Great Basin, southern Idaho, and Montana. In California, Los Angeles reported an average 68.2 F (20.1 C), 7.6 F (4.2 C) above normal and warmest March since records began in 1877. Los Angeles observed 6 days at or above 90 F (32.2 C), shattering the previous record of 3 March days above this threshold set 1934, 1988, and 1997. Further north, Sacramento reported its warmest March in a 139-year record at 63 F (17.2 C). Across the border to the east, Reno, Nevada set its March average temperature record at 52.1 F (11.2 C), 6.4 F (3.6 C) above normal. Records at Reno airport began in 1937. To the north, Portland, Oregon saw its warmest March since records began in 1938 at 52.4 F (11.3 C), or 4.2 F (2.3 C) above normal. In central Washington, temperatures at Moses Lake averaged to 48.1 F (8.9 C), the warmest in a 67-year record. Moving southeast, the March average at Pocatello, Idaho was 44.1 F (6.7 C), 6.1 F (3.3 C) above normal and the second warmest since records began in 1939. Salt Lake City, Utah saw its warmest March on record at 49.7 F (9.8 C). Records at Salt Lake City began in 1928. In Montana, Helena set the record for warmest March average temperature at 44.7 F (7.1 C), 8.4 F (4.7 C) above normal. To the southeast, Billings, Montana reported its earliest 80 F (26.7 C) day on record on March 28. The previous earliest 80 F reading was on March 31, 2012. This was also the second warmest March on record in Billings since observations began in 1934. In the Southwest, average March temperature in Flagstaff, Arizona was 42 F (5.6 C), the 3rd highest in a 123-year record.
A few locations in the Southwest recorded above normal precipitation due to a closed low-pressure system that moving across the region during the first week of the month. In southeastern California, Blythe received 1.02 in (26 mm) 204% of normal and the 8th wettest March in a 68-year record. Flagstaff, Arizona reported 3.73 in (95 mm) precipitation, 176% of normal. This was the 15th wettest March since records began in 1893. Both of these locations received nearly all their precipitation over the first two days of the month. Scattered areas along the northern tier of the west also saw above normal precipitation due to a series of storms in the latter half of the month. In the Idaho Panhandle, Bonners Ferry saw its 6th wettest March on record, observing 3.89 in (99 mm) precipitation this month, 234% of normal. Records at Bonners Ferry began in 1907. Further South, Spokane, Washington logged 2.43 in (62 mm) of precipitation, 151% of normal and the 15th wettest March in a 135-year record.
Drier than normal conditions prevailed elsewhere in the West, especially in California and the Great Basin. San Francisco observed 0.12 in (3 mm) for the month, 4% of normal and tied with 1956 for 4th driest March in a 167-year record. On the other side of the Sierra Nevada, Reno recorded only 0.01 in (0.4 mm) of precipitation, to tie 1997 for the 2nd driest March on record. The anemic snowpack in the Sierra Nevada, Cascades, and Great Basin continued to dwindle this month. A majority of basins reported less than 20% of normal snow water equivalent at month’s end. Snowpack in the Rockies had been near to slightly above normal throughout the winter, but above normal temperatures and below normal precipitation this month reduced snow water equivalents to 50-80% of normal in most basins. Drought conditions worsened in large areas of eastern and western Nevada, northern Utah, western Colorado, and along the Wyoming-Idaho border. Drought conditions improved in central and northern New Mexico.
Average temperatures were near to above normal throughout Alaska this month. Some locations in the Southwest, Interior, and Southcentral regions were significantly above normal despite a cold snap that affected the Interior between the 9th-16th. McGrath reported an average 17.6 F (-8 C), 6 F (3.3 C) above normal and the 9th warmest March since records began in 1941. Precipitation was highly variable across the state, though the North Slope saw above average precipitation. Barrow reported 0.28 in (7 mm), 311% of normal. Drier than normal conditions continued for much of Hawaii this month, most notably on the Big Island, Oahu, and Kauai. Honolulu received 0.62, in (16 mm), 31% of normal. In contrast, Kahului, Maui received 9.79 in (249 mm) of rainfall, 400% of normal and the 2nd wettest March since records began in 1905. Drought conditions eased this month in parts of the Big Island, Maui, and Moloka’i.
Significant Events for March 2015
March (all month): Record low snowpack in Sierra Nevada: Snow water equivalent on April 1 was only 5% of normal for the date. This was the lowest measurement since official records began in 1950. The previous lowest April 1 snow packs of 25% of normal were observed in 1977 and 2014. This prompts major concerns over water resources for the coming months. March 15: Strong winds in Portland, Oregon/Vancouver, Washington area: High winds and rain moved through the area on the 15th causing moderate damage. Gusts downed many trees and power lines and left 45,000 people without power in the afternoon. Fallen trees blocked roadways and caused damage to cars and buildings. In Portland, scaffolding fell off a building the downtown area.