Flood in Juneau Borough, Alaska

Moderate precipitation fell over the the Jordan Creek area in Juneau from the afternoon of September 29th to day break on September 30th. This precipitation of 1 to 1.5 inches of rain in 12 to 18 hours rose Jordan Creek to be just below bankful. Heavy rain associated with a strong atmospheric river moved into the area through the afternoon and evening hours of September 30th. Jordan Creek started to rise rapidly in response to the runoff from to the heavy rain through the night of September 30th with it going over moderate flood stage of 10.5 feet in the morning hours of October 1st from 1.5 to 2 inches in 12 hours. Jordan Creek crested at 10.98 feet in the late morning which was the the second highest crest on record from the 2 to 3 inches of rain that fell over the previous 24 hours. As the rain tapered off water levels dropped below minor flood stage by the late afternoon. There was significant flooding of roads, yards, parking lots around the Jordan Creek area and along Jordan Avenue. Some homes and business did get water into their buildings and caused some damage.

Southeast Alaska had been impacted by a number of atmospheric rivers through September to keep streamflow on small and large rivers high. Another atmospheric river lifted out of the north Pacific as the associated warm front moved over Southeast Alaska it produced heavy rain over the northern inner channels of the panhandle. The front also advected a lot of warm air with freezing levels near 10 thousand feet. The complex terrain of the region enhance the rainfall with 1.5 to 3.5 inches of rain fell over a 12 to 18 hour period.

The heavy rain and significant ice melt from the very warm temperatures in the headwaters of the Taiya River produced a lot of overland flow. This caused moderate flooding along the Taiya River from the early morning hours to the late afternoon on October 1st. There was road closures, damage to National Park Service infrastructure along the Chilkoot trail and near the Dyea campground. This was also the 4th highest peak flood on record. There was also moderate flooding along Jordan Creek in Juneau from the early morning to the afternoon hours on October 1st. The crested was the 2nd highest peak flood on record. A large landslide along the Haines Highway around 23 mile that came down in the overnight hours of October 1st and blocked the road. The area around the landslide reported 1 to 1.5 inches of rain in 12 hours.