Flood in Sitka Coastal, Alaska

It rained for thirty seven days with one day without any precipitation for a total of twenty two point nine inches over the Sitka area. The average daily rainfall for this time period was greater than one half of inch of rain per day. A strong weather front moved through the area and produced heavy rain of three point fifty six inches on January 14. This broke the previous daily record of three point twenty three inches from 1965. The very moist antecedent soil conditions, high rain rates along with strong winds gusts of forty five mph triggered land/mudslides and flooded lakes and rivers. A mudslide was triggered in the Cascade Creek Road neighborhood that damaged an apartment building that was knocked off it foundation along with mud and water in the building. There was visual reports that Cascade Creek was at flow levels not seen in twenty years. There was also numerous parking lots flooded and Indian River was flowing out of its banks flooding Indian River road and destroying the trail.

A strong and very moist weather front with a tropical connection moved across Southeast Alaska January 13 and 14. An anomalous ridge of high pressure set up over the eastern Pacific and western North America during the first week of January. The blocking ridge was oriented in a way that it steered a large plume of high precipitable water values northward. The associated atmospheric river moved into the eastern Gulf of Alaska from the North Pacific and then over the panhandle on January 14. The front produced strong wind gusts over the area as the front moved over the area. The combination of the wind and very wet soil conditions from almost 35 straight days of rain produced mud-slides over Prince of Wales Island, Ketchikan and Sitka areas near steep terrain and/or clear cut areas.