Status: ACTIVE — Flash Flood Warning until 3:45 AM CDT Saturday, September 19. The National Weather Service in La Crosse has issued a Flash Flood Warning for southern Fillmore County in southeastern Minnesota, effective 11:46 PM CDT Friday. Doppler radar and automated rain gauges indicate thunderstorms producing heavy rain across the warned area: between 1 and 3.5 inches of rain have fallen, with another 1 to 3 inches possible. Flash flooding is ongoing or expected to begin shortly.
This is the second of three active flash flood warnings across southeastern Minnesota tonight — a multi-county rain event that is still unfolding while most of the warned area sleeps. For restoration contractors, this is the overnight scenario that fills the Saturday call board: water moving into basements, crawl spaces, and low-lying commercial buildings hours before anyone is awake to see it. This is a live snapshot as of 12:30 AM CDT Saturday, September 19. Conditions change fast — always verify with the National Weather Service for your specific county or ZIP code.
Southern Fillmore County — Flash Flood Warning
Issued: 11:46 PM CDT Friday, September 18, by the National Weather Service in La Crosse (KARX).
Expires: 3:45 AM CDT Saturday, September 19.
Area: Southern Fillmore County in southeastern Minnesota.
Severity: Severe · Certainty: Likely · Urgency: Immediate.
At 11:46 PM CDT, Doppler radar and automated rain gauges indicated thunderstorms producing heavy rain across the warned area. Detection is radar and gauge indicated — automated gauges on the ground are confirming what the radar shows.
Rainfall totals so far, per the NWS:
- Between 1 and 3.5 inches of rain have fallen across the warned area.
- Additional rainfall amounts of 1 to 3 inches are possible in the warned area.
- Flash flooding is ongoing or expected to begin shortly.
HAZARD: Flash flooding caused by thunderstorms.
SOURCE: Radar and automated gauges.
IMPACT: Flash flooding of small creeks and streams, urban areas, highways, streets and underpasses as well as other poor drainage and low-lying areas.
Some locations that will experience flash flooding include: Preston, Spring Valley, Harmony, Mabel, Canton, Highland, Cherry Grove, Bristol, Newburg, Amherst, York, Carimona, Ostrander, Hutton, Granger, Forestville State Park, Greenleafton, and Henrytown.
Source links: NWS La Crosse office page · the official NWS alert (FFWARX).
Stay safe tonight
Turn around, don’t drown. When you encounter a flooded road, do not attempt to cross it — most flood deaths occur in vehicles, and even a few inches of fast-moving water can carry a car away. Be especially cautious tonight: it is harder to recognize the dangers of flooding after dark, and this warning runs until nearly 4 AM.
If water is entering your home:
- Stay out of standing water where electricity may be present. Do not enter a flooded basement until power is confirmed off.
- Avoid the basement until the water recedes and the electrical situation is verified safe.
- Photograph everything before cleanup begins. Documentation matters for insurance — shoot the water line, the affected rooms, and any damaged contents before anything is moved or torn out.
- Call a local restoration contractor quickly. Water left sitting starts a second wave of damage — saturated drywall, wicking into framing, and mold growth — within a day.
What this means for restoration teams
Southern Fillmore County is hill country — the Root River valley, steep bluffs, and towns like Preston, Lanesboro-area corridors, and Harmony sitting in drainage paths that concentrate runoff fast. With 1 to 3.5 inches already down and another 1 to 3 possible, this is exactly the profile that produces basement seepage, overwhelmed sump systems, and water pushing through foundation walls in older housing stock.
What to expect from the call volume:
- The wave starts at dawn. Overnight flash-flood calls typically surface between 5 and 8 AM as people wake to wet basements. Staff the phones for Saturday morning.
- Sump-pump failures will be a major call driver. When rain falls this fast on saturated ground, sump systems run continuously — and the ones with aging pumps or no battery backup fail at the worst moment. Ask callers whether they have a sump and whether it’s running.
- Rural properties and state-park-adjacent cabins are in the mix. Forestville State Park is inside the warned area, and seasonal properties with no one home are the jobs that get discovered days later — the mold jobs. If you serve the Preston/Spring Valley corridor, a Saturday drive-by route through low-lying areas can surface work before homeowners even call.
- Mold clock starts now. Porous materials soaked tonight reach the 24–48 hour mold window by Sunday. The contractors who win this wave are the ones with drying equipment staged and an on-call rotation already running.
The play: stage equipment now — dehumidifiers, air movers, extraction units, moisture meters. Keep an on-call rotation through Saturday morning. On the first call, capture the address, the water source (rain intrusion vs. sewage backup vs. sump failure), and every affected room. Photo-document before mitigation starts, moisture-map every affected room, and keep the homeowner’s payment responsibility clear in writing before work begins.
FEMA & federal assistance
If your home or business is damaged and a federal disaster is later declared for your county, help may be available through FEMA. The FEMA Helpline is 1-800-621-3362 (7 a.m.–10 p.m. local time, 7 days a week). You can also apply at DisasterAssistance.gov or through the FEMA app, and find recovery centers at fema.gov/drc.
Basic eligibility: U.S. citizenship or qualified status, identity verification, proof of occupancy or ownership of the damaged property, and unmet needs not covered by insurance. Apply as soon as it is safe to do so — and document your damage thoroughly before cleanup, because adjusters and FEMA inspectors both work from what you can show.
Looking ahead
This warning runs until 3:45 AM CDT — the longest of tonight’s southeastern Minnesota warnings — which tells you the NWS expects the heavy rain to persist. When it expires, the danger does not necessarily end: creeks and streams in Fillmore County can crest hours after the rain stops, and saturated bluff-country ground means even a light follow-up round can re-trigger flooding with almost no lead time. Watch for an extension or additional warnings from NWS La Crosse if rain rates hold.
The demand window for restoration work opens as the water recedes: water-intrusion calls typically start within hours and keep coming for days as people discover damage — wet carpet that seemed fine, baseboards that wicked overnight, musty odors that surface Sunday. Contractors who run Saturday-morning inspection routes through Preston, Spring Valley, and Harmony will find the work the overnight storm left behind.
Sources & how to verify
- NWS Flash Flood Warning FFWARX — official alert text
- NWS La Crosse office
- weather.gov — enter your county or ZIP code for your local warnings
To verify for your own county or ZIP: go to weather.gov, enter your location, and check the alerts box at the top of your local forecast page — or visit your NWS office page directly.
This post is for informational purposes and is not an official weather warning. Always follow instructions from local authorities and the National Weather Service.
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