60 flood insurance claims·$1.4M paid·5 federal flood & hurricane disasters
Share of the whole county outline, rivers and lakes included; parts FEMA hasn’t mapped count as zero.
Shaded areas are FEMA’s mapped flood hazard zones in and around Stillwater County, Montana. Zoomed out they are simplified; at street level the map switches to FEMA’s exact layer. Tap anywhere to check that spot, or search an address above.
Flash flooding from summer thunderstorms dominates Stillwater County, Montana, complemented by standard river floods. Over the past 30 years, the NOAA Storm Events Database recorded 12 flash flood events and 8 flood events. Recent events include multiple flash floods in June 2023, driven by moist easterly surface flow, high dewpoints, atmospheric precipitable waters over 1.00, and light upper-level winds that produced slow-moving, heavy thunderstorms.
National Flood Insurance Program claims data demonstrate that flood risks extend across multiple zones. Zone A accounts for 34 claims with an average payout of $37,489 and an average recorded water depth of 22 inches. Zone X recorded 12 claims with an average payout of $62,290 and an average water depth of 1 inch. Zone X_UNSHADED logged 10 claims averaging $342,8 payouts and an average water depth of 50 inches. Zone X_SHADED recorded 2 claims with an average payout of $750 and an average water depth of 0 inches, while Zone UNKNOWN logged 2 claims averaging $0 in payouts and 0 inches of water depth.
Property owners in Zone A and Zone X should pay the closest attention to flood risks, as these areas have accumulated the highest number of insurance claims and substantial average payouts.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
26% of Stillwater County’s flood insurance claims were on properties rated outside FEMA’s high-risk zones.
46 NFIP claims with a recorded rated flood zone, 1978 to date. The zone is the one FEMA used to rate that policy, which may not match today’s map. Source: OpenFEMA NFIP claims.
In flood insurance claims here that reported a flood depth, the average was 31 inches.
Drawn to scale against an 80-inch door. Even a few inches soaks flooring, the bottom of the drywall and anything plugged in near the floor.
Average of the depths reported on claims (zero and implausible values left out); FEMA’s record doesn’t say exactly where each depth was measured. Source: OpenFEMA NFIP claims.
The worst year was 2022, with 33 claims and $1.3M paid, the year of Severe Storm and Flooding.
Bar height is scaled by square root so ordinary years stay visible next to the worst one. NFIP claims by year of loss. Source: OpenFEMA.
9 NOAA storm reports from Stillwater County describe what happened, in the words of the forecasters who covered it. Read the Montana flood stories →
15 federal disaster declarations since 1978, 5 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Flooding | Jun 1, 2023 |
| Severe Storm And Flooding | Jun 10, 2022 |
| Falling Star Fire | Aug 2, 2020 |
| Flooding | Mar 20, 2019 |
| Ice Jams And Flooding | Mar 1, 2014 |
| Severe Storms And Flooding | Apr 4, 2011 |
| Eagle Mount Fire | Sep 3, 2009 |
| Derby Fire | Aug 30, 2006 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
20 since 1996: 12 flash floods and 8 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flash Flood | Jun 23, 2023 | — |
| Flash Flood | Jun 8, 2023 | — |
| Flash Flood | Jun 6, 2023 | — |
| Flash Flood | May 26, 2019 | — |
| Flood | Mar 23, 2019 | $804,000 |
| Flash Flood | May 23, 2018 | — |
| Flood | Mar 9, 2014 | — |
| Flood | Mar 6, 2014 | — |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flash Flood · Jun 23, 2023. A very moist, easterly surface flow returned during the 3rd week of June. Dewpoints were again well above 50 degrees, with many areas around 60 degrees. In addition, atmospheric precipitable waters were well over 1.00. Winds aloft continued to be light resulting in slow-moving, heavy thunderstorms. As a result, several flash flood events occurred across portions of central and southeast Montana.
Flash Flood · Jun 8, 2023. A very moist, easterly surface flow continued into the start of the second week of June. This resulted in dewpoints well above 50 degrees, as well as atmospheric precipitable waters over 1.00. Winds aloft continued to be light resulting in slow-moving, heavy thunderstorms. As a result, multiple flash flood events occurred across portions of central and south central Montana.
Flash Flood · Jun 6, 2023. A very moist, easterly surface flow advected 50 to 60 degree dewpoints from the central plains into the Billings Forecast Area. In addition, atmospheric precipitable waters were well over 1.00. Steering winds were light resulting in slow-moving thunderstorms. Although some large hail occurred with a few thunderstorms, the main impact was heavy rain and flash flooding.
Flash Flood · May 26, 2019. A strong jet streak moved over the forecast area during the late afternoon into the evening hours on the 26th. This jet streak provided for strong upper level divergence. |At the same time, a strong upper level disturbance moved over the forecast area. |All the above, combined with low-level moisture and wind shear, resulted in severe thunderstorms across portions of the Billings Forecast area.
National Weather Service narratives, lightly trimmed. Source: NOAA Storm Events Database.
Every colour on the map above is a place on this drawing: where the ground sits relative to the flood FEMA plans for.
If a building in Stillwater County is in a high-risk zone (A or V) and its mortgage comes from a federally regulated or insured lender, or is federally backed, flood insurance is required.
Outside those zones it is optional, and often worth having: from 2014 to 2024 nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area. Since Risk Rating 2.0, NFIP premiums are set for each building, so the only reliable price is a quote: FloodSmart.gov or a local agent.