Photo: Bryan Housel · CC BY-SA 3.0On FEMA’s figures, Mountainside faces less hazard damage per building than 62% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Mountainside gets a B for hazard risk: lower expected damage per building than 62% of U.S. towns, #138 of 468 in New Jersey. Most of that expected damage is river and rain flooding (83%). Flood insurance has paid 15 claims here since 1979.
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 Mountainside 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
Earthquakes
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 Mountainside’s grade
River and rain flooding is 83% of the building damage FEMA expects in Mountainside, and Mountainside’s rate of river and rain flooding damage is higher than 59% of U.S. census tracts. Next is earthquakes at 8% (higher than 72% of U.S. census tracts).
B #138 of 468 in New Jersey; lower expected damage per building than 62% of U.S. towns (21,298).
All of Mountainside’s residents live in one census tract; the figures are that tract’s.
The typical New Jersey town has higher expected damage than 56% of U.S. towns; within the state, Mountainside has less expected damage per building than 71% of New Jersey towns.
In dollars, FEMA expects about $2.6M a year in losses across Mountainside: $2.3M to buildings, the rest to people and crops.
Does Mountainside flood? Sometimes: 15 flood claims since 1979
Every paid claim on a federal flood insurance policy in Mountainside, from FEMA’s records: 5.8 per 1,000 homes, more than 64% of the 13,809 U.S. towns with a flood insurance record.
- Hurricane Irene4 claims · $86K
- Hurricane Ida3 claims · $174K
Mountainside isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Union County.9 federal disasters brought FEMA money to Mountainside
Disasters that paid out in Mountainside itself (aid to households or repair grants to the Borough of Mountainside), newest first, with that year’s flood claims.
- 2021Remnants of Hurricane Ida58 households applied for aid$179K aid approved3 flood claims paid for it, $174K
- 2016Severe Winter Storm and Snowstorm$97K to the Borough of Mountainside for repairs
- 2012Hurricane Sandy131 households applied for aid$19K aid approved$379K to the Borough of Mountainside for repairs
- 2011Severe Storm$27K to the Borough of Mountainside for repairs
- 2011Hurricane Irene57 households applied for aid$71K aid approved$73K to the Borough of Mountainside for repairs4 flood claims paid for it, $86K
- 2010Severe Winter Storm and Snowstorm$51K to the Borough of Mountainside for repairs
Show all 9
- 2010Severe Storms and Flooding4 households applied for aid$2K aid approved
- 2007Severe Storms and Inland and Coastal Flooding11 households applied for aid$9K aid approved1 flood claim paid that year
- 1999Hurricane Floyd Major Disaster Declarations$19K to the Borough of Mountainside for repairs1 flood claim paid for it, $10K
Union County has had 21 natural disasters declared by the President since 1953, most often severe storms, then hurricanes and tropical storms. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees; the 2001 World Trade Center declarations.
Old photos of Mountainside after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Mountainside archive →Mountainside and its neighbors
Mountainside is 2nd of the 4 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 |
|---|---|---|---|
| Westfield | B+less damage than 70% | river and rain flooding | 45 |
| Mountainside | Bless damage than 62% | river and rain flooding | 15 |
| Summit | B−less damage than 53% | river and rain flooding | 61 |
| Berkeley Heights Township | C+more damage than 62% | river and rain flooding | 67 |
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 Mountainside 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.
- Drop, cover and hold on.
- Strap tall furniture and the water heater to the wall.
- Know how to shut off the gas.
- 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.
Know where neighbors sign up for alerts? Add it to the Handbook so everyone has it.
Questions about natural hazards in Mountainside
Is Mountainside at risk for natural disasters?
On FEMA’s National Risk Index, Mountainside has lower expected damage per building than 62% of U.S. towns: B for hazard risk, #138 of 468 in New Jersey. Most of the expected damage is river and rain flooding (83%) and earthquakes (8%). The figures are for the one census tract the town shares with its neighbors. This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Mountainside flood?
Flood insurance has paid 15 claims in Mountainside since 1979, $330K in all, or 5.8 per 1,000 homes, more than 64% of U.S. towns with a flood insurance record. 2 properties have flooded more than once. The most claims came from Hurricane Irene (4).
Is Mountainside 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 Union County, 49% of homes in mapped flood zones carry federal flood insurance, and 2.9% of all homes do.
How much is flood insurance in Mountainside?
FEMA’s Community Rating System list shows no discount for Mountainside’s flood program. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.
What was the biggest storm in Mountainside?
By FEMA money that reached Mountainside, Hurricane Sandy (2012): 131 households applied for aid, $19K approved, and $379K to the Borough of Mountainside for repairs. By flood claims, Hurricane Irene: 4 paid, $86K.
Is Mountainside at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (83%), and Mountainside’s rate for it is higher than 59% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Mountainside.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Mountainside’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.