A significant flash flood warning for Brown, Door, Kewaunee, Oconto, Outagamie counties is currently in effect across portions of northeast Wisconsin, as heavy thunderstorms move through the region. The National Weather Service (NWS) in Green Bay issued the alert late Monday evening, April 13, after Doppler radar indicated intense rainfall capable of causing immediate and dangerous flooding.
The warning, which remains active until 4 a.m. CDT, targets several specific zones: northern Brown County, southern Door County, northern Kewaunee County, southern Oconto County and northeastern Outagamie County. Residents in these areas are urged to avoid travel and seek higher ground if they are in flood-prone locations.
Meteorologists report that the situation is evolving rapidly. As of 10:01 p.m. CDT, radar data showed that between 1 and 2 inches of rain had already fallen across the warned areas. With additional rainfall of 0.5 to 1.5 inches possible, the ground is becoming saturated, increasing the likelihood of sudden runoff and rising water levels.
Rainfall totals and radar analysis
The current weather system is characterized by slow-moving thunderstorms that are dumping high volumes of water over concentrated areas. According to the National Weather Service, this type of heavy precipitation often leads to flash flooding, which is defined as a sudden flood caused by excessive rainfall in a short window—typically less than six hours.
Because flash floods can develop in minutes and occur even in areas that are not currently receiving rain, the NWS has emphasized that the danger is not limited to the immediate center of the storm. The primary hazard remains the rapid accumulation of water in areas with poor drainage.
High-risk locations and urban impact
The impact of the storm is expected to be most severe in urban centers, low-lying areas, and near small creeks and streams. Highways, city streets, and underpasses are particularly vulnerable to rapid flooding, which can trap motorists or wash away sections of the roadway.
Several communities are specifically highlighted as high-risk areas for flash flooding. These include:
- Major Hubs: Green Bay, De Pere, and Sturgeon Bay.
- Residential and Suburban Areas: Howard, Ashwaubenon, Allouez, Bellevue, and Suamico.
- Smaller Municipalities: Algoma, Luxemburg, Pulaski, Oneida, Hobart, Little Suamico, Chase, Abrams, Pensaukee, Humboldt, and Brussels.
Officials warn that the combination of nighttime visibility and rising waters makes the current window especially perilous. It is often demanding to recognize the depth or speed of floodwaters when driving at night, increasing the risk of vehicles being swept off the road.
Safety protocols: ‘Turn around, don’t drown’
The NWS has issued a stark reminder for those encountering water on the roads: “Turn around, don’t drown.” This directive is based on the fact that the majority of flood-related fatalities occur inside vehicles. Just two feet of moving water can be enough to sweep away most cars, including SUVs and trucks.
For those currently in the affected counties, emergency management suggests the following safety measures:
| Action | Reasoning / Detail |
|---|---|
| Avoid Driving | Road damage may be hidden beneath water; vehicles can be swept away. |
| Avoid Walking | Six inches of quick-moving water can knock an adult off their feet. |
| Move to High Ground | Immediate relocation is necessary for those in low-lying or flood-prone areas. |
| Monitor Alerts | Leverage battery-operated radios or mobile notifications for real-time updates. |
parents are cautioned to keep children away from flowing water, as currents can be deceptive and may hide dangerous debris, rocks, or steep drop-offs.
Understanding the alert level
It is important for residents to distinguish between a “watch” and a “warning.” A flash flood watch indicates that conditions are favorable for flooding to occur. However, a flash flood warning—which is currently in effect—means that flooding is imminent or already occurring. In this stage, the time for preparation has passed, and the time for immediate action has begun.
For those seeking the most current local updates, the NWS Green Bay office provides the most authoritative data on storm movement and warning expirations.
The current warning is set to expire at 4 a.m. CDT, though meteorologists will continue to monitor radar for any necessary extensions or novel warnings as the system progresses. Residents should remain alert and keep weather notifications enabled on their devices through the early morning hours.
We invite readers to share this update with neighbors in the affected counties and leave comments below regarding local road conditions to help others stay safe.
