Gates of The Arctic National Park and Preserve/Bettles Weather Summary Fall 2021, Winter 2021-2022, and Spring 2022

Summer field trip to Killik climate station on a calm morning in July.

NPS/Travis Monahan

We monitor and record weather data in Gates of the Arctic National Park & Preserve to help understand daily, monthly, and seasonal weather patterns and shifting climate averages that influence the health and abundance of the plants and animals that live in the park and the hydrologic systems that support them. We also track the weather extremes that cause disturbance such as drought, floods, heat waves, cold snaps, and high winds. The data are collected and analyzed along with other park ‘vital signs’ to provide a holistic view of how these high latitude park lands are changing. The weather station in Bettles has been recording temperature and precipitation data for over seventy years. We use that information to provide context for the changes we are seeing today inside the park.

Climate stations in Gates of the Arctic National Park & Preserve.

Fall of 2021 was slightly cooler than normal overall and the total precipitation was slightly below normal

The average temperature for the fall season in Bettles was 0.2°F cooler than the 1991-2020 normal (30-year average). Although the temperatures averaged near normal for the season, October was much warmer than normal (+5.9°F), and November was much cooler than normal (-5.2°F) (Fig. 1). September was also on the cooler side; 1.3°F cooler than normal. It was the 7th warmest October on record in Bettles with >70 years of observations. November 2021 was the coldest November to date at the Pamichtuk station (30 miles SW of Anaktuvuk Pass). We started recording the temperature at this site in 2013. The November monthly temperature is, on average, -13°F at this site, in 2021 it was -19°F.

The two stations in the western region of the park, Ram Creek above the Alatna River and Killik Pass, also had the coldest Novembers to date with average temperatures of -18°F and -22°F, respectively. The October monthly temperatures at these sites, unlike Bettles, was not warmer than average. The record for these sites is shorter, dating back about a decade, during which time Alaska experienced some of the warmest temperatures on record.

October was a snowy month for Bettles. A total of 20.5 inches of snow fell during the month, normal is 12 inches. The November snowfall total was 7 inches shy of normal. Overall, the fall season had a total of 4.07 inches of precipitation (rain and melted snow) between September 1 and November 30, slightly below the normal 4.45 inches (Table 1).

Figure 1. Fall 2021 daily temperatures at Bettles showing record maximum (red), record minimum (blue), normal (brown) and observed range (blue bars).

Table 1. Bettles fall 2021 average monthly and seasonal  temperature and precipitation totals and departure from the 1991-2020 normal.

The winter of 2021/2022 was cool and wet

December brought extreme precipitation and rain-on-snow along the West Coast of Alaska and into Interior Alaska. Heavy snowfall, freezing rain, and rain brought record amounts of precipitation to many communities. Bettles included. It was the wettest December on record! 3.61 inches of precipitation was recorded in December (melted snow, sleet, rain), which is 345% of normal. There were several very wet days in December. The wettest day was December 6 when 9.1 inches of snow fell with a water content of 1.07 inches. There were three waves of storms that came through Bettles in December. December 5-7 saw a total snowfall of 17 inches; December 18-20 brought an additional 9 inches; and a third storm system December 25-29 brought another 16 inches of snow. The late December plume of moisture impacted most of the communities along the west coast of Alaska into the central Interior of the state north of the Alaska Range with widespread rain-on-snow. Farther north in the mountains of Gates of the Arctic NP&P temperatures warmed to a maximum of ~22°F during the warm December events, so precipitation likely fell as snow rather than rain (Fig. 2). Precipitation in January was near normal in Bettles, but the February total was < 50% of normal. The winter season precipitation total was 4.97 inches, 2 inches above normal. It was the 5^th wettest winter season on record in Bettles.

Winter temperatures for 2021-2022 continued the cooler than normal trend with the persistence of a La Niña into a second winter season. La Niña, in general, means cooler temps for Alaska (Fig. 3). Each month of the winter season had cooler than normal winter temperatures. December temperatures were just below normal, January was 1.2 degrees F cooler than normal, and February was the chilly winter month with an average temperature > 6 degrees cooler than normal (Table 2). A few warm periods occurred in late December and late February. Even with cooler than normal temperatures, a new record high of 34°F was observed on December 20 (Fig. 4).

Figure 2. December 2021 daily air temperatures at the climate stations in Gates of the Arctic National Park and Preserve.

Figure 3. During a La Niña event the winter temperatures are often cooler than normal in Alaska due to the position of the Pacific and Polar jet streams. The winters of 2020 and 2021 were both La Niña winters.

Courtesy NWS/NCEP Climate Prediction Center.

Figure 4. Winter 2021/2022 daily temperatures at Bettles showing record maximum (red), record minimum (blue), normal (brown) and observed range (blue bars).

Table 2. Bettles winter 2021/2022 average monthly and seasonal  temperature and precipitation totals and departure from the 1991-2020 normal.

The spring season was warm and dry

The average spring season temperature was +1.8°F warmer than the seasonal normal, mostly due to warmer than normal temperatures in March. March was 5.8 degrees F warmer; April was just below normal, and May was just above normal (Fig. 5). With an average temperature of 26.3°F spring of 2022 was > 5 degrees F warmer than the spring of 2021. With 10 years of record at Chimney Lake (10 miles east of the ‘Gates of the Arctic’ on the North Fork of the Koyukuk River), spring of 2022 was the 4^th warmest spring to date. The coolest spring was 2013 (13.1°F) and the warmest was 2019 (25.1°).

The spring is generally the driest season for the region and this spring was no exception. The spring season total was only 0.84 inches, most of that fell as rain during the first part of May. Normal spring precipitation is 2.10 inches.

Figure 5. Spring 2022 daily temperatures at Bettles showing record maximum (red), record minimum (blue), normal (brown) and observed range (blue bars).

Table 3. Bettles spring 2022 average monthly and seasonal  temperature and precipitation totals and departure from the 1991-2020 normal.

A camera at the Pamichtuk climate station provides useful information on snow accumulation, melt-out, green up, and vegetation changes. This year melt-out was approximately April 30th.

NPS/Pamichtuki Climate Station

Bettles Seasonal Snowfall

Bettles is one of the few remaining long-term weather stations that continues to measure daily snowfall. The 2021-2022 seasonal snowfall total was above normal at 106.6 inches (Fig 6). It was the 14th snowiest season on record in Bettles. The recent winters of 2017/18, 2018/19, and 2019/20 all had higher snowfall totals.

The melt-out date in Bettles (date of last persistent winter snow) was May 14. Using images from a camera onsite at the Pamichtuk climate station we determined that the mountain site melted out around April 30 (right). There was still patchy snow in the area, but most of the immediate area was snow free by then.

Figure 6. Seasonal snow accumulation for the 2021/22 season at Bettles (green line). The brown line shows the 1991-2020 normal snow accumulation.

Summer 2022 (through August 11)

The average monthly temperature for June was near normal. June rainfall was below the 1991-2020 normal with a total of 0.96 inches, normal is 1.46. There was little accumulation after mid-month, and without rain the region was prime for fire starts from lightning. Most of the fire activity was south of the park, but several fires were discovered inside the park boundary. A map from the Eastern Area Fire Management team from July 18 shows the fire perimeters near the park (Fig 7.) The average temperature for July was 58.9°F, almost a degree cooler than normal. Total rainfall was 90% of normal, with most of that falling during the latter part of the month. The first few days of August were warm, after that a cold front moved in and temperatures dropped below normal. As of August 11th, the rainfall total for August is right at normal. We’ll update the full summer statistics in the fall.

Figure 7. Wildland fires in and around Gates of the Arctic National Park and Preserve. Map courtesy of the Eastern Area Fire Management Team  - July 18, 2022.

For more info, contact:

Pam Sousanes, Physical Scientist
907-455-0677
[e-mail]

Ken Hill, Physical Scientist
907-455-0678
[e-mail]