U.S. River Conditions, January to March 2021

This is an animation showing the changing conditions of USGS streamgages from January 1, 2021 to March 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.

In January, the Pacific Northwest (particularly, western Oregon and Washington) experienced higher-than-normal water due to an atmospheric river. Simultaneously, North and South Carolina had high water and flooding that lasted through the end of the month. Meanwhile, much of the West and Southwest were dry, with over 90% of Utah experiencing extreme drought into late January. Along the coast of California, there was some relief from dry conditions due to an atmospheric river moving through in early February. Throughout February and into early March, the Southeastern coast was hit by multiple weather fronts, which brought successive periods of high water and some flooding. Heavy rain coupled with melting snow brought about high flow conditions and flooding in Washington state at the end of February. In early March, Puerto Rico experienced moderate drought conditions. Intense rain over Hawaii in the middle of March resulted in flooding on multiple islands, most notably a new record-high water level at USGS gage 16587000 in East Maui which has been recording river conditions for 108 years. Dry conditions in the Southwest did not ease as drought persisted through the end of March. In the final days of March, the Midwest and Northeast experienced higher-than-normal flows and flooding in a number of places.

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.