The National Weather Service office in Wilmington, Ohio, issued a Flash Flood Warning for Mercer County, Ohio, at 3:09 AM EDT on September 16. The warning remains in effect until 7:00 AM EDT. A Flash Flood Warning means flooding is occurring or imminent in the warned area — this is the most urgent flood alert the NWS issues, and it calls for immediate action rather than simple awareness.
Residents in Mercer County — including communities such as Celina, Coldwater, and St. Henry, along with rural areas near the Wabash and St. Marys rivers and their tributaries — may notice rapidly rising water on roads, creeks spilling out of their banks, and standing water in low-lying areas and underpasses. Overnight flash flooding is especially dangerous because it is harder to see water depth on roads in the dark.
What to do right now
If you are in Mercer County: avoid driving through flooded roads entirely — most flood deaths happen in vehicles, and six inches of moving water can knock a person down while two feet can carry away a car. If you live in a flood-prone or low-lying area, be ready to move to higher ground quickly, and keep a phone and flashlight close by since this warning runs through the early morning hours. Never walk or drive around barricades.
Keep an eye on updated forecasts from the NWS through the morning, as the warning could be extended or additional counties could be added if heavy rain continues. Once the warning expires, remain cautious around swollen creeks and rivers, which can continue rising even after the rain stops.
This alert is based on data issued by the National Weather Service (NWS) Wilmington, Ohio office.
Frequently Asked Questions
What should I do right now if I'm in Mercer County?
Stay off flooded roads and move to higher ground if water is rising near your home. Do not attempt to drive or walk through floodwater, especially in the dark before dawn.
How long will this warning last?
The current warning runs until 7:00 AM EDT on September 16. The NWS may extend it or issue new warnings if heavy rain continues, so keep monitoring local alerts through the morning.
Is a Flash Flood Warning worse than a Flood Watch?
Yes. A watch means flooding is possible; a warning means flash flooding is happening or imminent right now. Treat this as an immediate-action alert, not just a heads-up.
Will rivers in the area keep rising after the warning expires?
Possibly. Rivers and creeks like the Wabash and St. Marys can crest hours after heavy rain ends, so avoid riverbanks and low-water crossings even later in the day.
Keep tracking this:
Source: National Weather Service (NWS)
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Sky & Solar Conditions at the Time
Moon: Waxing Crescent (27% illuminated), in Scorpio.
Notable planetary angles: Sun sextile Mars (61°), Sun sextile Moon (62°), Moon trine Mars (123°), Mercury opposite Saturn (176°).
Concurrent space weather: planetary Kp index 2.3; strongest recent solar flare: nothing notable.
This is a factual snapshot, not a claim of cause and effect – researchers are divided on whether lunar, planetary or solar factors influence seismic or weather activity. It’s included so readers can track the pattern for themselves over time.
