Flood in Juneau Borough, Alaska

Heavy rain moved into the Juneau area in the late afternoon of September 20th and continued to increase through the overnight hours with 1.5 to 2 inches of rainfall by 0700AKDT. Jordan Creek near the Juneau airport start to respond to this heavy rain with a sharp rise upward and went over minor flood stage of 9.7 feet in the early morning hours of September 21st. As the heavy rain continued, Jordan Creek rose to be just under moderate flood stage of 10.5 feet by the afternoon. A second pulse of heavy rain moved over the area in the evening and overnight hours of the 21st and this additional 1 to 1.5 inches of rain pushed Jordan Creek above moderate flood stage. The creek crested at 10.77 feet in the early morning hours of Friday September 22nd. As the heavy rain diminished with the AR pushing east into Canada, Jordan Creek fell below moderate flood stage by mid morning and then below minor flood stage in the afternoon.

There was moderate flooding around Jordan Creek which impacted roads, business and a few homes. The severity of the impacts was water getting into a few homes and crawlspaces, over driveways and around entrances to businesses. Meanwhile, shortly after 12AM on the 22nd, water coming down the hillside in downtown Juneau resulted in a few homes being evacuated.

A storm force weather front along with a strong Atmospheric River (AR) associated with this system moved into the central Gulf of Alaska through the morning hours of September 20th. As the AR push east over southeast Alaska through the afternoon and evening hours of September 20th heavy rain moved over the central and north central inner channels. This heavy rain persisted into Thursday September 21st and a mesoscale frontal wave formed along the cold front which stalled the heavy rain and high rain rates over the central and north central inner channels through the evening and early morning hours of Friday September 22nd. The AR pushed east of the area by late Friday morning into the afternoon hours. Strong wind gusts from 40 to 55mph were reported at sea level with higher winds gusts at high elevation weather stations as system moved through the area.

The region received from 3 to 6 inches with localized higher amounts near 9 inches at higher elevation sites. Most of the precipitation fell on September 21st. This persistent heavy rain produced minor flooding along small and flashy streams like Indian River near Sitka in the evening of September 20th, Montana Creek and Auke Lake near Juneau on September 21, and along Falls Creek near Petersburg on September 21 into the 22nd. Jordan Creek in Juneau did produce moderate flooding and impacted a few homes in the area through the evening of September 21 and then the morning hours of the 22nd.