Alaska is having a rough summer. Following a July that was Alaska’s hottest month on record, erratic and unusual precipitation totals have caused downpours in some parts of the state and sparked fires and water restrictions in others.

14-day observed precipitation, Aug. 20 1 inch or less 8 inches or more RUSSIA Chukchi Sea Bering Sea Nome Prudhoe Bay Bethel Alaska Denali Nat’l Park Fairbanks McKinley Fire Swan Lake Fire Anchorage Yukon Territory Pacific Ocean Juneau British Columbia 300 MILES Ketchikan 14-day observed precipitation, Aug. 20 Less than 1 inch 8 inches or more RUSSIA Nome Prudhoe Bay Bethel Alaska Denali Nat’l Park Fairbanks McKinley Fire Swan Lake Fire Anchorage Yukon Territory Pacific Ocean Juneau British Columbia 300 MILES Ketchikan 14-day observed precipitation, Aug.20 Less than 1 inch 8 or more inches RUSSIA North Nome Fairbanks is on pace for one of the ten wettest months on record. Bethel Alaska Denali Nat’l Park Fairbanks McKinley Fire Anchorage Swan Lake Fire Pacific Ocean Anchorage has received little precipitation and the air has been warm and smoky from nearby wildfires. Yukon Territory Southeast Alaska, known as a temperate rainforest, has been below normal for rainfall in August, but Ketchikan just broke a 90-year record for daily rainfall yesterday with 4.85 inches of rain. Juneau British Columbia Ketchikan 300 MILES

August and September are typically the wettest months for Alaska. Northern Alaska, including Fairbanks, has been inundated with precipitation this month due to an atmospheric river event. Meanwhile in Southern Alaska, Anchorage received only trace amounts of rain in August, and only a quarter-inch of rain fell on Ketchikan, where water restrictions were being enforced until a heavy rain event Wednesday.

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This lack of precipitation is also contributing to wildfires. Alaska’s fire season typically ends in July with the onset of August precipitation, but last weekend, dry conditions and high winds sparked a new fire, the McKinley Fire, just north of Anchorage along Parks Highway, destroying about 50 structures. These conditions also ramped up the already existing Swan Lake Fire in the Kenai Peninsula that was mostly contained, spreading smoke across Anchorage and a large swath of South-central Alaska. In Anchorage, air quality has been among the poorest observed in the United States this summer.

Wildfire areas burning on August 19 To Denali National Park ALASKA Detail McKinley Fire Willow Smoke Smoke Anchorage Whittier Smoke Swan Lake Fire Seward Homer 50 MILES Wildfire areas burning on August 19 To Denali National Park ALASKA Detail McKinley Fire Willow Smoke Smoke Anchorage Whittier Smoke Swan Lake Fire Seward Homer 50 MILES Wildfire areas burning on August 19 To Denali National Park ALASKA Detail McKinley Fire Willow Smoke Smoke Anchorage Whittier Smoke Swan Lake Fire Seward Homer 50 MILES Wildfire areas burning on August 19 To Denali National Park ALASKA Detail McKinley Fire Smoke Willow Smoke Anchorage Whittier Smoke Swan Lake Fire Seward Smoke Homer 50 MILES

“In most years, the season really ramps up around the first of June and reliably dies down by the first of August. Occasionally, the fire season lasts well into August,” said Brian Brettschneider, a researcher for the University of Alaska at Fairbanks at the International Arctic Research Center. While in the Lower 48 it can take months for vegetation to dry out enough to fuel fires, in Alaska, black spruce forests can be susceptible to fires after only a few days of dry conditions.

This is not a record fire year for Alaska, but it is a significant one with more than 2 million acres burned. The amount of acres burned due to wildfires throughout Alaska’s recorded fire history is variable, but the frequency of fire seasons where 2 million acres or more are burned has increased in recent years.

Acres burned in Alaska 6 million 4 11-year rolling avg. 2 0 1950 1960 1970 1980 1990 2000 2010 2019 Acres burned in Alaska 6 million 4 11-year rolling average 2 0 1950 1960 1970 1980 1990 2000 2010 2019 Acres burned in Alaska 6 million 4 11-year rolling average 2 0 1950 1960 1970 1980 1990 2000 2010 2019 Acres burned in Alaska 6 million 4 11-year rolling average 2 0 1950 1960 1970 1980 1990 2000 2010 2019

The setup for this extended fire season was exacerbated by unusually warm temperatures early in the summer. Anomalous warmth in the past year, as well as warmer-than-usual waters in the surrounding Bering, Chukchi, and Beaufort seas and the North Pacific Ocean fueled the warm and humid conditions experienced by Alaskans.

Sea surface temperature anomaly, August 19 9˚F below normal 9˚F above normal No data RUSSIA Prudhoe Bay Bethel Alaska Anchorage U.S. CANADA Yukon Territory Pacific Ocean Juneau British Columbia Sea surface temperature anomaly, August 19 9˚F below normal 9˚F above normal No data RUSSIA Nome Prudhoe Bay Bethel Alaska U.S. CANADA Anchorage Yukon Territory Pacific Ocean Juneau British Columbia Sea surface temperature anomaly, August 19 9˚F below normal 9˚F above normal RUSSIA No data Nome Prudhoe Bay Bethel Alaska U.S. CANADA Anchorage Yukon Territory Pacific Ocean Juneau British Columbia

This “bathtub” of warm water surrounding Alaska helped contribute to higher-than-normal temperatures, especially overnight lows that trended higher than normal. In Anchorage, June and July were the warmest months ever recorded, with nighttime lows that rarely dropped below 50 degrees for most of the summer. In a city with buildings designed to keep warmth in, this has been problematic for residents.

Daily temperatures in Anchorage On July 4, Anchorage set a record high of 90 degrees 90°F Record highs 80 70 60 Normal temp. range 50 Between June 21 and Aug. 18, the low temperature did not drop below 50 degrees, the second-longest stretch on record. 40 Record lows 30 20 June 1 July 1 Aug. 1 Daily temperatures in Anchorage On July 4, Anchorage set a record high of 90 degrees 90°F Record highs 80 70 60 Normal temp. range 50 Between June 21 and Aug. 18, the low temperature did not drop below 50 degrees, the second-longest stretch on record. 40 Record lows 30 20 June 1 June 15 July 1 July 15 Aug. 1 Aug. 15 Daily temperatures in Anchorage On July 4, Anchorage set a record high of 90 degrees 90°F Record highs 80 70 60 Normal temperature range 50 Between June 21 and Aug. 18, the low temperature did not drop below 50 degrees, the second-longest stretch on record. 40 Record lows 30 20 June 1 June 15 July 1 July 15 August 1 August 15 Daily temperatures in Anchorage On July 4, Anchorage set a record high of 90 degrees 90°F Record highs 80 70 60 Normal temperature range 50 Between June 21 and Aug. 18, the low temperature did not drop below 50 degrees, the second-longest stretch on record. 40 Record lows 30 20 June 1 June 15 July 1 July 15 August 1 August 15

Anchorage has seen 14 nights dropping below 50 degrees this summer. The only other time the city saw so few was in 2016, when they had only 13 such nights. From 1952 to 2012, Anchorage had only five nights that failed to drop below 60 degrees. This summer, they have had 9 of those nights.

The warmer-than-usual waters are not expected to cool anytime soon, which will likely lead to a milder fall and early winter period. Alaskan firefighters who normally transition to firefighting in the Lower 48 in August continue to battle the fires back home.

About this story

Precipitation data from National Weather Service. Satellite imagery from NASA Worldview. Fire history data sourced from the Alaska Interagency Coordination Center and the Alaska Forestry Service. Sea surface temperature anomaly data from NOAA. Anchorage daily temperature data from National Weather Service.

Andrew Freedman and Tim Meko contributed to this report.