2016-2019 Southeast Alaska Drought
Overview
From late 2016-summer 2019, Southeast Alaska experienced below average precipitation and above average temperatures. While there was variability between seasons, low precipitation (compounded by high evaporation in the warm summer) led to water shortages, hydroelectric power restrictions, wildfires, insect outbreaks, and more. Some impacts hit within the first year, while others occurred as a result of multiple years of water and heat stress. Climate models predict that drought risk will decrease in Southeast Alaska by 2050 due to increased precipitation, but increased temperatures could counteract this, complicating the model’s conclusions.
Weather Woes
Storms that bring rain to Southeast Alaska typically form near the Aleutian Islands and track into the Gulf of Alaska, following a fairly reliable path into the Panhandle. These storms are associated with low pressure, where air rises, cools, and produces clouds and precipitation. From 2016 to 2019, that pattern often shifted. Frequent high pressure over the Aleutians altered the usual storm track, steering many systems farther north into Interior Alaska instead of the Panhandle. High pressure is associated with sinking, drying air, which suppresses cloud formation and precipitation. As a result, Southeast Alaska experienced more frequent clear conditions and below-normal rainfall, leading to drought impacts in a region that typically depends on steady, reliable precipitation.
Drought Formation
Typical conditions (low pressure), heavy precipitation Drought conditions (high pressure), dry air
Changing pressure systems in the Aleutians and resultant storm patterns, graphic by Heather McFarland (ACCAP)
Weather Patterns
The October 2016–September 2019 drought period was both drier and warmer than usual, especially in the southern Panhandle. The dryness was persistent in both winter and summer. Summers were consistently warmer than normal except for a few months of normal temperatures near Haines. Summer 2019 stood out as exceptionally warm across all of Southeast Alaska.
Departures from normal precipitation and temperature patterns in Southeast Alaska, figure by Rick Thoman (ACCAP)
Impact Timeline
Some impacts occur after only a short period of dryness. For example, surface soils and ground cover can dry out rapidly, which can increase wildfire risk. Communities like Wrangell, with limited water storage capacity, can run low on water after only a few months. Other impacts take a year or more to materialize. For example, it took two years of drought for the massive Snettisham Reservoir feeding Juneau to drop low enough to restrict power to Green Creek Mine.
Spring 2017: Wrangell declared a water emergency
Summer 2018: Wildfires in the Tongass National Forest peaked in summer 2018
Wildfire in Juneau on May 31, 2018 Summer 2018: Poor berry crop in Metlakatla
Summer 2018, Summer 2019: Hemlock Sawflies spread across the region from 2018-2019
Hemlock sawfly damage (yellowed trees), photo by Elizabeth Graham Fall 2018: Power was cut off to Juneau’s Green Creek Mine in Fall 2018
Green Creek Mine, photo by Hecla Mining Spring 2019: Macaulay Salmon Hatchery moved juvenile salmon prematurely due to warm waters
Spring 2019: Reservoirs feeding Ketchikan and Metlakatla hydropower dropped, both communities relied on diesel generators
Spring 2019: Haines issued a water restriction when Lily Lake reached a record low
Water pump near Lily Lake at low levels, photo by Chilkat Valley News
Regional Impacts
Insect outbreaks
A hemlock sawfly outbreak across southeast Alaska began in 2018, ultimately defoliating 530,000 acres of forest. Sawfly are always present in southeast Alaska, but in normal, cool, and wet summers, fungal diseases keep sawfly numbers down. The drought limited this fungal growth, allowing sawfly larval populations to grow to outbreak status.
Wildfire and Smoke
Regional drought conditions and warming temperatures increase the risk of wildfire in Southeast Alaska and other nearby regions. Smoke from wildfires in regions like the Yukon Territory and northern British Columbia regularly moves over Southeast Alaska, and high pressure commonly associated with drought conditions helps trap smoke near the ground, worsening air quality and visibility. During the 2016-2019 drought, Southeast Alaska reported more smoke than usual. Juneau had three days in July 2019 with dense smoke that reduced visibility to six miles or less. Most years Juneau experiences no dense wildfire smoke.
Community Specific Impacts
Angoon: Hemlock Sawfly Outbreak damage in Hood Bay. photo by USDA Forest Service Robin Mulvey
Photo of hemlock sawfly damage in Hood Bay near Angoon. Photo by USDA Forest Service Robin Mulvey
Haines: Issued water restrictions due to record low levels of Lily Lake, which provides 80% of water, water stopped flowing by gravity and had to be pumped, reduced water reaching the community by 50%
Juneau: Electric power restricted and increased in price; hydroelectric power cut off at Greens Creek Mines due to low water levels at Snettisham Reservoir; Macauly Salmon Hatchery released some juveniles early due to warm water; 3 days where wildfire smoke reduced visibility to 3 miles
Wrangell: Repeated water restrictions due to low reservoir levels, declared water emergency
Ketchikan: Increased and repeated reliance on diesel for electricity (rather than hydropower)
Photo of low water exposing the banks of a reservoir near Ketchikan. Photo by Jeremy Bynum
Metlakatla: Water use restrictions; power produced by diesel due to low water levels; poor berry crop limited subsistence
Photo of low water levels at Purple Lake, the source of Metlakatla’s water supply. Photo by Genelle Winter, Metlakatla Indian Community
Sitka: Minimal impacts due to 2014 improvements in water storage infrastructure at Blue Lake Dam
References
Hoell, A., Thoman, R., McFarland , H. R. & Parker, B. 2022. Southeast Alaska drought [report]. International Arctic Research Center, University of Alaska Fairbanks.