Photo: Billy Hathorn · CC BY-SA 3.0On FEMA’s figures, Longmont faces about as much hazard damage per building as the typical U.S. town, mostly from river and rain flooding
On FEMA’s National Risk Index, Longmont gets a B− for hazard risk: lower expected damage per building than 53% of U.S. towns, #61 of 159 in Colorado. Most of that expected damage is river and rain flooding (71%), then hail (11%). Flood insurance has paid 50 claims here since 1981.
Graded on FEMA’s expected yearly building damage per dollar of building value (NRI v1.20, December 2025), weighted by where residents live; flood claims are shown, not graded. How hazard risk is graded
What stands out about Longmont’s natural hazards
From FEMA’s model and FEMA’s records, below.
What Longmont faces
Each hazard’s share of the building damage FEMA expects here, and how its rate compares with the rest of the country.
River and rain flooding
Hail
Tornadoes
Shares are of FEMA’s expected building damage, the measure the grade uses; ranks compare each hazard’s building-damage rate with all 85,154 U.S. census tracts. In FEMA’s terms, river and rain flooding is FEMA’s “Inland Flooding” (rivers and streams overflowing their banks, or rain overwhelming drainage). FEMA defines coastal flooding as high or rising tides and storm surge, so surge damage is counted there. Drought isn’t listed: FEMA counts its losses in crops only.
What’s behind Longmont’s grade
River and rain flooding is 71% of the building damage FEMA expects in Longmont, and Longmont’s rate of river and rain flooding damage is higher than 54% of U.S. census tracts. Hail adds 11%, at a rate in the top 7% of U.S. census tracts.
B− #61 of 159 in Colorado; lower expected damage per building than 53% of U.S. towns (21,298).
Longmont’s residents live in 23 census tracts; FEMA’s figures are combined by where they live.
The typical Colorado town has higher expected damage than 56% of U.S. towns; within the state, Longmont has less expected damage per building than 62% of Colorado towns.
Among the 400 U.S. cities of 100,000 or more, Longmont has lower expected damage per building than 64% (#145 of 400). Because it is so big, its total expected yearly loss, $26.8M, is the 365th largest of those 400.
Does Longmont flood? Sometimes: 50 flood claims since 1981
Every paid claim on a federal flood insurance policy in Longmont, from FEMA’s records: 1.1 per 1,000 homes, fewer than 75% of the 13,809 U.S. towns with a flood insurance record.
- The Late summer storms46 claims · $4.6M
Longmont is in FEMA’s Community Rating System (class 5) for its flood-proofing work.
Insurance rates: Boulder County.5 federal disasters brought FEMA money to Longmont
Disasters that paid out in Longmont itself (aid to households or repair grants to the City of Longmont), newest first, with that year’s flood claims.
- 2021Wildfires and Straight-line Winds58 households applied for aid$500 aid approved
- 2015Severe Storms, Tornadoes, Flooding, Landslides, and Mudslides$1.1M to the City of Longmont for repairs
- 2013Severe Storms, Flooding, Landslides, and Mudslides2,253 households applied for aid$7.6M aid approved$42.0M to the City of Longmont for repairs46 flood claims paid that year
- 2006Snow$96K to the City of Longmont for repairs
- 2003Snow$11K to the City of Longmont for repairs
Boulder County has had 8 natural disasters declared by the President since 1953, most often floods, then severe storms. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Also 7 FEMA wildfire suppression grants (Fire Management Assistance, not a disaster declaration) for fires in Boulder County, 2000–2024.
Old photos of Longmont after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Longmont archive →Longmont and its neighbors
Longmont is 2nd of the 2 graded towns here, from least expected damage per building to most. Tap a town to see its hazards.
| Town | Hazard risk | Mostly (buildings) | Flood claims |
|---|---|---|---|
| Firestone | Bless damage than 63% | river and rain flooding | 6 |
| Longmont | B−less damage than 53% | river and rain flooding | 50 |
Hazard risk = FEMA’s expected yearly building damage per dollar of building value, vs. the 21,298 U.S. towns we grade; the map is shaded by fifths of the same scale. Flood claims = paid federal flood insurance claims on record.
Get ready for what Longmont faces
A short kit for the hazards that drive the building damage here, what to check before you buy, and where neighbors get alerts.
- Turn around at flooded roads: a foot of moving water can carry off a car.
- Flood insurance usually takes 30 days to start, so buy it before the forecast.
- Keep papers and medicines up high, in a grab-and-go bag.
- Park in a garage or under cover when storms are forecast.
- Stay away from windows while it falls.
- Photograph roof and car damage for your insurer.
- Pick your spot now: the lowest floor, an inside room, no windows.
- A watch means be ready; a warning means take cover now.
- Keep shoes and a flashlight by the bed.
- Look up the address on FEMA’s flood map.
- Ask the seller or landlord whether it has ever flooded, and what flood insurance costs there.
- Get a flood insurance quote early: policies usually start 30 days after you buy.
- Longmont residents get 25% off flood insurance.
Know where neighbors sign up for alerts? Add it to the Handbook so everyone has it.
Questions about natural hazards in Longmont
Is Longmont at risk for natural disasters?
On FEMA’s National Risk Index, Longmont has lower expected damage per building than 53% of U.S. towns: B− for hazard risk, #61 of 159 in Colorado. Most of the expected damage is river and rain flooding (71%) and hail (11%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Longmont flood?
Flood insurance has paid 50 claims in Longmont since 1981, $4.6M in all, or 1.1 per 1,000 homes, fewer than 75% of U.S. towns with a flood insurance record. The most claims came from Late summer storms (46).
Is Longmont in a flood zone?
Flood zones are drawn street by street, so the answer depends on the address: look it up on FEMA’s flood map. In Boulder County, 44% of homes in mapped flood zones carry federal flood insurance, and 2.3% of all homes do.
How much is flood insurance in Longmont?
Longmont is in FEMA’s Community Rating System (class 5), which takes 25% off federal flood insurance policies for its flood-proofing work. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.
What was the biggest storm in Longmont?
By FEMA money that reached Longmont, Severe Storms, Flooding, Landslides, and Mudslides (2013): 2,253 households applied for aid, $7.6M approved, and $42.0M to the City of Longmont for repairs. By flood claims, Late summer storms: 46 paid, $4.6M.
Is Longmont at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (71%), and Longmont’s rate for it is higher than 54% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Longmont.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Longmont’s residents lived in the 2020 census; OpenFEMA: NFIP redacted claims, multiple-loss properties, community status book and residential penetration rates, housing assistance (owners and renters), public assistance funded projects, hazard mitigation properties and disaster declarations. Homes: Census ACS 2020–24. Preparedness tips: Ready.gov. FEMA’s model is an average of expected damage, not a forecast. How hazard risk is graded.