August in the West
Many locations in the West experienced wetter than normal conditions this month as an active monsoon pattern and slow-moving low-pressure systems enhanced thunderstorm activity. Persistent low pressure over the coast and frequent thunderstorms in the Southwest acted to moderate temperatures in these areas. Strong high pressure over the central and southern Rockies brought record high temperatures to the inland Northwest. Several large fires burned throughout the West, impacting air quality and visibility.
On the heels of one of the driest Julys on record, August brought scattered heavy precipitation to the Northwest. Wenatchee, in central Washington, received 1.91 in (48 mm) of rain and logged its second wettest August since records began in 1959. Of this total, 1.09 in (28 mm) fell in one hour on August 1st. Redmond, Oregon saw 1.16 in (29 mm) precipitation, 232% of normal and the 8th wettest August in a 67-year record. Areas of Nevada also experienced heavy monsoonal precipitation. Rainfall in Reno totaled 1.08 in (27 mm), the 4th wettest August in the past 77 years. Needles, in California’s Mojave Desert, recorded 2.84 in (72 mm), nearly 600% of normal and the 4th wettest in a 66-year record. Significant monsoon moisture also reached northern Arizona, southern Utah, and parts of Colorado. Flagstaff, Arizona had its 11th wettest August on record at 4.85 in (123 mm), 156% of normal. During July and August, Colorado Springs logged 10.33 in (262 mm) rainfall, the second wettest such period in 66 years. Areas of near-normal summer rainfall helped to alleviate some of the exceptional drought in southeastern Colorado.
Following a wet July, August precipitation totals were lackluster in southern Arizona and New Mexico. Tucson, Phoenix, and Yuma, Arizona all reported below normal precipitation for the month. After receiving nearly 200% of normal precipitation in July, Albuquerque, New Mexico, received 0.42 in (11 mm), a scant 30% of its normal August precipitation. This summer’s precipitation did help to improve drought conditions throughout the state. After a drier than normal summer, severe drought continued for much of western Wyoming. Riverton reported only 0.05 in (1 mm) for the month, 10% of normal. Some improvements in drought conditions were seen in the northeastern portion of the state where normal rainfall totals were received this summer.
Many coastal areas saw persistent fog and slightly cooler than normal temperatures. Los Angeles, California reported 22 days with fog this month, 5 days above the average 17 and was 1.0 F (0.5 C) cooler than the August average. Meanwhile, temperatures soared throughout the inland Northwest. Daily temperatures in Salt Lake City, Utah averaged 82.7 F (28.2 C) for the month, the hottest August in a 140-year record. This was also Salt Lake’s warmest summer at an average 80.7 F (27.1 C). Boise, Idaho also saw its warmest summer on a 74-year record at an average 76.5 F (24.7 C). Following its all-time hottest month in July, Yakima, Washington averaged 73.2 F (22.9 C) this month, a tie with 1961 for second warmest August since records began in 1947. Temperatures were also warmer than normal throughout Montana; Billings averaged 75.0 F (23.9 C), the 8th warmest in an 80-year record. Elsewhere in the region, Laramie, Wyoming recorded its 2nd warmest summer since records began in 1948 at an average 64.3 F (17.9 C).
August wrapped up a warmer than normal summer for much of Alaska. On August 8th, Fairbanks hit its 36th day in a calendar year with a high over 80 F (26.7 C). This breaks the record of 30 days set in 2004. However, on the last day Bettles fell to a frosty record 15 F / -9.4 C. Southern Alaska was wetter than normal with Kodiak and Cold Bay both logging their second wettest August on record at 9.3 in (236 mm) and 6.49 in (165 mm), respectively. Further south, dry conditions continued to dominate throughout Hawaii with most stations across the state reporting less than 50% of normal rainfall. A few locations, such as Molokai and Kaneohe, Oahu logged above normal precipitation.
Significant Events for August 2013
August (all month): Wildfires in the West: Though many large fires burned throughout the West this month, year-to-date the nationwide number of fires is 64% of the 10-year average and acres burned stands at 63% of the 10-year normal. The largest fires include: Rim Fire, California: This fire began August 17, cause unknown. It has since charred over 230,000 acres (93,077 hectares) and become the 4th largest fire in California history. Smoke transported by southwesterly flow brought hazardous air quality to downwind locations such as the Lake Tahoe Basin and west-central Nevada including Reno and Carson City. Beaver Creek and Elk Complex Fires, Central Idaho: These lightning-caused fires began August 7th and 8th and grew to over 110,000 acres (44,575 hectares) and 130,000 acres (52,609 hectares), respectively before they were both contained on the 31st.
August 9th: Flash flooding in Manitou Springs, Colorado: The burn scar from last year’s Waldo Canyon fire made this area of central Colorado susceptible to flash flooding. The flood resulted in one fatality, six houses destroyed and 11 damaged, along with 40 cars stranded and broken gas, sewer, and water pipes. This was the third flash flood in Manitou Springs this year.
August (throughout month): Flooding in Las Vegas, Nevada: Several instances of flash flooding occurred this month throughout the greater Las Vegas area impacting travel and damaging roadways.