Deep low pressure tracked northward along the outer coast causing impacts across Southeast Alaska beginning Halloween night through November 2nd. High Winds were felt over the outer coast and heavy rain caused rivers to rise out of their banks across the southern half of Southeast Alaska with minor impacts. The ground was already saturated by moderate to heavy rain leading up to November 1 and 2 with amounts ranging from 5 to 9 inches. Multiple mudslides occurred near steep terrain after rain amount of 3.5 inches over 36 hrs along with wet antecedent soil conditions. Tight pressure gradient along the Coast Mountains resulted in strong northerly outflow winds and cold air to push southward through the northern inner channels resulting in heavy snow.

Debris Flow in SITKA COASTAL, ALASKA
From 01-NOV-20 17:00:00 to 02-NOV-20 06:00:00 (AKST-9)
Location: SITKA
Flood cause: Heavy Rain
Property damage: 35.00K
Crop damage: 0.00K
Reported by: Public

It had been very wet in the area with 3 to 5 inches of rain over the 3 previous days. Heavy rain from an atmospheric river moved into the Sitka area on November 1 and persisted into the morning of November 2 with an additional 3 to 5 inches of rainfall. Rain rates were greater than 0.5 inches per hour. The heavy rain along with the already saturated soils increased the risk of debris flow near steep terrain. In the early evening of November 1 a debris flow blocked Sand Dollar Road. One lane was cleared for travel in the evening but another debris flow came down during the overnight hours going into November 2 and the road was blocked again. One home at the top of Sand Dollar Road was not damaged but was now on a earth cliff that needed an engineering assessment for safety reasons. Overall there were around 18 debris flows from October 26-November 2. There was also extensive flooding around the Indian River and caused damage to the dam and fresh water diversion for the Sitka Sounds Science Center's hatchery. There was damage to the dam and the road to the water intake was washed. At the hatchery the motors for the drum screen that filters the fresh water were overrun, burned out and destroyed the motor and pumps.

Debris Flow in CRAIG COASTAL, ALASKA
From 01-NOV-20 17:00:00 to 02-NOV-20 10:00:00 (AKST-9)
Location: CRAIG
Flood cause: Heavy Rain
Property damage: 200.00K
Crop damage: 0.00K
Reported by: Local Official

It had been very wet in the area with 3 to 5 inches of rain over the 3 previous days. Heavy rain from an atmospheric river moved over western Prince of Wales Island on November 1 and persisted into the morning of November 2 with an additional 3 to 5 inches of rainfall. Rain rates ranged from 0.30 to 0.40 inches per hour. The heavy rain along with the already saturated soils increased the risk of debris flow near steep terrain. A debris flow was initiated above Port St. Nicholas road and blocked the single lane road to a subdivision with mud, trees and other debris. This blocked the road going to Craig, the main town in the area.

High Wind in CAPE DECISION TO SALISBURY SOUND COASTAL AREA, ALASKA
From 01-NOV-20 19:03:00 to 01-NOV-20 19:22:00 (AKST-9)
Magnitude: 55.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Peak wind gust of 63 mph measured at the Sitka Airport during the evening of November 1st.

Heavy Snow in JUNEAU BOROUGH AND NORTHERN ADMIRALTY ISLAND, ALASKA
From 01-NOV-20 12:25:00 to 02-NOV-20 09:55:00 (AKST-9)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Rain changed to snow around noon on the 1st and quickly accumulated 7 inches by 5 PM as measured by an NWS Employee on Douglas Island. Snow continued through the night and occasionally mixed with ice pellets and freezing rain the morning of the 2nd. The greatest snowfall measurement was 11.5 inches at midnight by a CO-OP observer at Lena Point. Multiple power outages were reported between the early evening of the 1st through the morning of the 2nd.

Heavy Snow in GLACIER BAY, ALASKA
From 01-NOV-20 11:56:00 to 02-NOV-20 09:45:00 (AKST-9)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow began around noon on the 1st and accumulated 8.9 inches by 5 AM on the 2nd as measured by a Co-Op in Gustavus. The greatest snowfall measurement was 12 inches at 9 AM by trained spotter.

Heavy Snow in EASTERN CHICHAGOF ISLAND, ALASKA
From 01-NOV-20 11:56:00 to 02-NOV-20 09:45:00 (AKST-9)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Snow fell across the Hoonah area with a Co-Op observer measuring 11 inches at 845 AM on the 2nd.

Blizzard in TAIYA INLET AND KLONDIKE HIGHWAY, ALASKA
From 01-NOV-20 17:00:00 to 02-NOV-20 11:45:00 (AKST-9)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

The Skagway ASOS reported heavy snow and visibility quickly falling to 1/4 mile at the beginning of the event. Meanwhile the DOT RWIS sensor at White Pass was already measuring wind gusts out of the north of around 35 mph. These conditions continued into the morning of the 2nd. By 630 AM DOT reported the road closed and of 12 to 15 inches of snow near sea level. Later in the morning Skagway Customs reported 2 to 3 foot drifts.

Blizzard in HAINES BOROUGH AND LYNN CANAL, ALASKA
From 01-NOV-20 17:00:00 to 02-NOV-20 09:15:00 (AKST-9)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

The Haines ASOS reported heavy snow and visibility quickly falling to 1/4 mile at the beginning of the event. Meanwhile the wind was already reporting gusts of around 30 mph and marine points further south were reporting much higher winds. These conditions continued into the next morning with the ASOS exceeding wind gusts of 35 mph after 1 AM. Haines DOT reported blizzard conditions, blowing and drifting snow on the highway. Haines Customs reported 14 inches of snow in 24 hours and the Co-Op and spotters around town and Mud Bay measured 16 to 22 inches with mention of blowing and drifting snow.