Flood in South Slopes of the Central Brooks Range, Alaska

Up to 1.5 inches of warm rain fell on remaining snowpack across the Central Brooks range resulting in a rapid rise of the Middle Fork of the Koyukuk River between Coldfoot and Wiseman. Late evening on Monday the 15th, the public reported that water was moving over the road to Wiseman. A social media comment on the NWS Warning post came in just after midnight on the 16th stating that the water was high enough that it would be very difficult if not impossible to get in or out of Wiseman by road. In addition the NWS received reports from the general public stating that the water came up very fast, but did begin to slowly subside through the day on the 16th as the rain tapered off and came to an end.

Middle June saw a disturbance track over the Central Brooks Range resulting in anywhere from 1 to 1.5 inches of rain in about a 24 hour period. While most rivers were ice free, plenty of snowpack remained across the higher slopes. With high temperatures generally in the 60's and overnight lows remaining above freezing, excessive snowmelt combined with heavy rainfall lead to rapid rises along area streams and rivers, including the Middle Fork of the Koyukuk River. As a result, flooding was reported from Coldfoot to Wiseman.