16 flood insurance claims·$245,117 paid·1 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 Big Horn 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 and river flooding from seasonal snowmelt and heavy rains dominate the flood profile. Over the past 30 years, the NOAA Storm Events Database recorded 13 flash floods resulting in 1 death, alongside 11 general flood events.
Specific historical events illustrate these risks. In March 2019, warming temperatures melted considerable snow while ground temperatures remained frozen, preventing absorption and causing widespread flooding worsened by ice jams. In May 2019, several days of heavy rain combined with snowmelt from the northern Big Horn Mountains to cause flooding across Big Horn, Yellowstone, and Powder River counties. Summer thunderstorms also produce significant flash flooding, driven by slow-moving storms with high precipitable water values, such as the event in June 2023.
FEMA National Flood Insurance Program records show claims across various zones, with the highest average payouts occurring in Zone A at $57,761 with an average recorded water depth of 2 inches. Zone X_UNSHADED averaged $18,359 in payouts with a 3-inch average water depth, while Zone UNKNOWN averaged $4,352 with a 1-inch average depth. Zone X recorded an average payout of $297 with a 10-inch average water depth, and Zone D recorded zero payouts. Homeowners, real estate agents, and journalists working with properties located in mapped special flood hazard areas like Zone A, as well as unshaded Zone X areas, should pay the closest attention to these flood risks.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
In flood insurance claims here that reported a flood depth, the average was 3 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 1978, with 7 claims and $29,868 paid, the year of Severe Storms & 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.
4 NOAA storm reports from Big Horn County describe what happened, in the words of the forecasters who covered it. Read the Montana flood stories →
8 federal disaster declarations since 1978, 1 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Pf Fire | Jul 28, 2021 |
| Severe Storms And Flooding | Apr 4, 2011 |
| Hurricane Katrina Evacuation | Aug 29, 2005 |
| Severe Winter Storms | Apr 8, 2001 |
| Wildfires | Jul 13, 2000 |
| Severe Storms & Flooding | May 29, 1978 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
24 since 1996: 13 flash floods and 11 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flash Flood | Jun 8, 2023 | — |
| Flood | May 27, 2019 | — |
| Flash Flood | May 26, 2019 | — |
| Flood | Mar 23, 2019 | — |
| Flood | Jun 1, 2015 | — |
| Flood | Mar 7, 2014 | — |
| Flood | Mar 6, 2014 | — |
| Flood | May 30, 2013 | — |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
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.
Flood · May 27, 2019. Several days of heavy rain, combined with snow melt from the northern Big Horn Mountains, resulted in areas of flooding across portions of Yellowstone, Big Horn and Powder River Counties.
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.
Flood · Mar 23, 2019. Flooding occurred across many areas of south central and southeast Montana during the latter portions of the month. A considerable snow cover existed through the month. Surface and sub-surface ground temperatures remained frozen through the last week of March. Warming temperatures resulted in this snow to quickly melt. Widespread flooding occurred due to the snow melt not being able to soak into the ground. In ad…
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 Big Horn 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.