U.S. River Conditions, October to December 2021

This is an animation showing the changing conditions of USGS streamgages from October 1, 2021 to December 31, 2021. The river conditions shown range from the driest condition seen at a gage (red open circles) to the wettest (blue closed circles). A purple outer ring around a gage indicates it is flooding.

For the entirety of this quarter, extreme drought persisted in much of the West. From October 14 to October 20, South Central Texas faced localized flooding. From October 24 to October 31, an atmospheric river brought high water to California and Nevada. Starting on October 25 and ending November 1st, there was flooding in the Northeast and the Midwest. Atmospheric rivers caused flooding in Washington and Oregon from November 11 to December 1. Rain brought some relief to drought conditions in Hawaii over the month of December, while parts of the Eastern U.S experienced higher than normal river conditions. From December 10 to December 16, an atmospheric river brought heavy rain and snow to the Western U.S.

Note that both USGS gage height and National Weather Service flood stage levels are necessary to determine flooding conditions and were available for 38% of streamgages at the time this graphic was produced. Only publicly available data from the National Water Information System Website was used and some gages are missing gage height even when they have flow.