Mad River near Arcata, CA
River level and flood forecast · Humboldt County
The river is 16.3 ft below flood stage (22 ft).
Forecast to hold near 5.7 ft through Sat, Oct 17, 5 AM.
Flow: 49 cubic feet per second (USGS).
The last 7 days and the forecast
NWS forecast issued Mon, Oct 12, 7:30 AM. Forecasts change as rain falls and as upstream water arrives.
Get flood alerts for this river
An email when the National Weather Service forecasts Mad River near Arcata to flood, when it floods, and when it's over.
Flood stages
| Major flood stage | 28 ft |
| Moderate flood stage | 24 ft |
| Flood stage | 22 ft |
| Action stage | 15 ft |
| Record crest (December 22, 1964) | 32.7 ft |
What floods at each level
From the National Weather Service, highest first.
- 33 ftDisastrous flooding of all areas near the river from Blue Lake to the mouth. The river is forecast to exceed record levels. All roads in the vicinity of the river are likely to be inundated and travel will be severely restricted. Residents should be prepared to take appropriate action to protect lives and property. This would include homes in Blue Lake, Tyee City and the Arcata Bottoms, as well as US Highway 101 between Arcata and Mckinleyville.
- 32 ftDisastrous flooding of all areas near the river from Blue Lake to the mouth. The river is forecast to exceed record levels. All roads in the vicinity of the river are likely to be inundated and travel will be severely restricted. Residents should be prepared to take appropriate action to protect lives and property. This would include homes in Blue Lake, Tyee City and the Arcata Bottoms, as well as US Highway 101 between Arcata and Mckinleyville.
- 30 ftExtensive, severe flooding of all low lying areas near the river from Blue Lake downstream to the mouth. Residents in these areas should be prepared to take appropriate action to protect lives and property. Critical locations include residential areas of Blue Lake, Tyee City, and the Arcata Bottoms, as well as US Highway 101 near Janes Road and areas near Giuntoli Lane.
- 28 ftSevere flooding of all low lying areas near the river from Blue Lake downstream to the mouth. Residents in these areas should be prepared to take appropriate action to protect lives and property. This includes residential areas of Tyee City and the Arcata Bottoms, US Highway 101 near Janes Road, areas near Giuntoli Lane, and Mad River Beach Road.
- 26 ftSevere flooding along Mad River Beach Road and extensive flooding of farmlands and other roads in the area. Flooding of residential areas around Tyee City is likely. Any low lying areas near the river could be flooded. Residents in these areas should be prepared to take appropriate action to protect lives and property.
- 24 ftExtensive flooding along Mad River Beach Road and adjacent farmlands. Some homes along the river could be threatened. Flooding of roads to Tyee City. High tides and strong onshore winds will enhance flood impacts.
- 23 ftSignificant flooding of portions of Mad River Beach Road and adjacent farmlands is likely. May cause water to flow across roads to Tyee City. High tides and strong, onshore winds will aggravate flood impacts.
- 22 ftSignificant flooding of portions of Mad River Beach Road. Water may flow across roads to Tyee City. Flood impacts will be aggravated by high tides and strong, onshore winds.
- 21 ftFlooding of Mad River Beach Road. Water may be flowing over roads to Tyee City. Flooding will be enhanced if the time of the crest is coincident with high tides and strong onshore winds.
- 18 ftMinor flooding of Mad River Beach Road near Tyee City.
- 15 ftMinor flooding begins on the Mad River Beach Road near Tyee City.
Highest crests on record
- 32.7 ft — December 22, 1964
- 28.43 ft — December 22, 1955
- 27.26 ft — January 13, 2024
- 25.46 ft — January 1, 1997
- 25.4 ft — March 2, 1972
Recent crests: 24.76 ft (December 21, 2025) · 21.34 ft (February 3, 2025) · 21.57 ft (December 29, 2024) · 27.26 ft (January 13, 2024) · 20.9 ft (March 14, 2023)
Up and down the river, and nearby
Not an official source. River levels, forecasts, flood stages and impacts are from the National Weather Service (ARCC1); flow from the U.S. Geological Survey. Readings are provisional. In a flood, follow your local officials and the NWS at weather.gov.