A Hamilton County flood watch takes effect at 2 p.m. Wednesday and runs through Thursday morning, as the National Weather Service warns that slow-moving thunderstorms could dump enough rain to trigger flash flooding.
Forecasters say 1 to 3 inches of rain are possible this afternoon and tonight, with locally higher totals not ruled out. The concern is “training” thunderstorms — repeated cells moving over the same areas along a slow-moving front — combined with ground that is already saturated from recent rainfall. That combination, the weather service said, “could quickly lead to flash flooding.”
Excessive runoff may cause flooding of rivers, creeks, streams and other low-lying, flood-prone spots. Creeks and streams may rise out of their banks.
The watch covers a wide swath of Indiana beyond Hamilton County, including Boone, Clinton, Hancock, Hendricks, Howard, Johnson, Madison, Marion, Morgan, Rush, Shelby and Tipton counties in central Indiana; Delaware, Henry and Randolph counties to the east; Carroll County to the north; and Fountain, Montgomery, Parke, Putnam, Tippecanoe, Vermillion and Warren counties to the west.
County’s outlook is more measured
Hamilton County Emergency Management struck a calmer tone in a social media update, saying scattered showers and storms may produce periods of heavy rainfall but that no major flooding is expected. Water levels could rise slightly before receding again, the agency said, urging residents to stay aware of changing conditions and use caution near waterways.
The two messages are not in conflict so much as different in scope: a flood watch means conditions are favorable for flash flooding, not that flooding is occurring or certain. Because the storms are expected to be scattered, the areas that happen to sit under repeated downpours could see problems even if the county as a whole stays dry enough to avoid significant flooding.
What to do
The weather service advises residents to monitor later forecasts and be prepared to act if flash flood warnings are issued. A warning — as opposed to a watch — means flooding is imminent or already happening and requires immediate action.
Basic precautions apply through Thursday morning:
- Never drive through flooded roadways. Most flood deaths occur in vehicles, and it takes only a foot of moving water to sweep a car away.
- Avoid low-lying areas, underpasses and parking lots that hold water.
- Keep children and pets away from swollen creeks and drainage ditches.
- Have a way to receive warnings overnight, when flash flooding is hardest to see.
More flood safety information is available at weather.gov/safety/flood.