Boston

City of Boston · City dashboard

Last verified: May 2026
Hazards
19
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Primary Hazard Profile

19 hazards documented · 7 citywide exposure · 0 worsening with climate change

19
hazards documented
7
citywide exposure
0
worsening trend
HazardExposureSeverityProbabilityClimate trendSource
Coastal Flooding4.2.3

No additional detail indexed.

source
Neighborhood-specific
If a storm surge of 5 feet coincided with the high tide, approximately 132 miles of roadway could be flooded; would leave drivers stranded, affect pedestrians, bicyclists...
High frequency event; may occur more frequently than once in five years, or greater than 20% chance per year (as defined by the 2013 Massachusetts State Hazard Mitigation...
increase|high
source
Dam Failure4.3

No additional detail indexed.

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Neighborhood-specific
Two types: catastrophic failure (sudden, rapid, uncontrolled release of impounded water) and design failure (minor overflow events).
Very low frequency; may occur less frequently than once in 100 years (less than a 1% chance per year).
increase|low
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Drought4.9

No additional detail indexed.

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Neighborhood-specific
Five drought severity levels: Normal (Level 0), Mild Drought (Level 1, >20 and ≤30% frequency, Advisory), Significant Drought (Level 2, >10 and ≤20%, Watch), Critical Dro...
Mild Drought (Level 1): >20 and ≤30% frequency; Significant Drought (Level 2): >10 and ≤20% frequency; Critical Drought (Level 3): >2 and ≤10% frequency; Emergency Drough...
increase|high
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Earthquake4.6.1

No additional detail indexed.

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Neighborhood-specific
Measured by Richter Scale and Modified Mercalli Intensity (MMI) scale.
PGA of 14-20 %g with a 2% probability of exceedance in 50 years; smaller earthquakes average about two occurrences per year; probability of a magnitude 5.
no_change|low
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Extreme Cold4.8.1

No additional detail indexed.

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Citywide
Wind chill of 0°F or below for three hours or more triggers extreme cold recognition; alerts range from Extreme Cold Weather Advisory (0°F to -14°F, 3+ hours), Wind Chill...
Medium frequency event; events occur from once in five years to once in 50 years, or 2% to 20% per year
unclear|low
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Extreme Heat4.8.2

No additional detail indexed.

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Citywide
Heat Advisory when Heat Index reaches 100-104°F for two or more hours; Excessive Heat Warning if Heat Index reaches 105°F or higher for two or more hours
Between four and five heat waves occur annually in Massachusetts; Boston experiences on average 14 days above 90°F annually (2000-2020), with a maximum of 27 days in 2002...
increase|high
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Fire Related Hazards4.7

No additional detail indexed.

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Neighborhood-specific
Brushfires measured by acres burned; influenced by fuel type, terrain, and weather.
Brushfires: medium frequency, likely to occur between once every five years to once every fifty years.
increase|medium
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Heavy Snow and Blizzard4.5.1

No additional detail indexed.

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Neighborhood-specific
Heavy snow: 4" or more in 12 hours or less, or 6" or more in 24 hours or less.
High frequency; can occur more than once in five years (greater than 20% chance of occurring each year).
unclear|low
source
Hurricanes and Tropical Storm4.4.3

No additional detail indexed.

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Citywide
Tropical storm: sustained winds 39–73 mph; Hurricane Category 1: 74–95 mph (minimal damage) through Category 5: >155 mph (catastrophic damage); wind gusts may exceed sust...
Medium frequency event; can occur between once in five years to once in 50 years (2% to 20% chance per year); return period for a Category 2 hurricane is approximately 1...
increase|medium
source
Ice Storm4.5.2

No additional detail indexed.

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Citywide
Ice storm severity can range from an inconvenience, lasting for a short duration, or debilitating and lasting for several days.
Medium frequency events; occur between once in five years to once in 50 years (a 2% to 20% chance of occurring per year) across the state.
unclear|low
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Landslides4.6.2

No additional detail indexed.

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Neighborhood-specific
Landslide intensity ranges from slight to very high, measured by volume and velocity: fast moving (rock fall) ranges from slight intensity (<0.
—
increase|medium
source
Nor'easters4.4.4

No additional detail indexed.

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Citywide
Storm radius up to 1000 miles or greater; sustained wind speeds of 20 to 40 mph; short-term gusts up to 50 to 60 mph; storm surge equal to or greater than two feet; condi...
Occur on at least an annual basis; high frequency events; may occur more frequently than once in five years (greater than 20% chance per year); since 2010, twenty-six nor...
increase|medium
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Riverine Flooding4.2.1

No additional detail indexed.

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Neighborhood-specific
a few inches to a few feet in depth; isolated flooding can leave one neighborhood inaccessible while an adjacent neighborhood remains safe; severity dependent on duration...
High frequency event: occurs more frequently than once in five years or greater than 20% per year; 100-year floodplain (Zone A) = 1% annual chance; 500-year floodplain (Z...
increase|medium
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Severe Thunderstorm4.4.1

No additional detail indexed.

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Citywide
Thunderstorms are typically less severe than other wind related hazard events in Boston.
High frequency; may occur more frequently than once in 5 years (a greater than 20% chance per year).
increase|medium
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Stormwater Flooding4.2.2

No additional detail indexed.

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Neighborhood-specific
primarily a nuisance that can dissipate within a few hours, but under some circumstances can cause serious property damage and put people at risk; flood waters can range...
High frequency event; may occur more frequently than once in five years, or greater than a 20% chance each year; on average stormwater flooding in Boston occurs at least...
increase|high
source
Tidal Flooding4.2.4

No additional detail indexed.

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Neighborhood-specific
Short duration due to cyclical tidal fluctuations; exacerbated when high tide coincides with intense rainfall, increasing threat to infrastructure.
High frequency hazard; may occur more frequently than once in five years, or greater than 20% chance per year (per 2013 Massachusetts State Hazard Mitigation Plan).
increase|high
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Tornados4.4.2

No additional detail indexed.

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Citywide
Winds may reach 300 miles per hour; damage paths in excess of one mile wide and 50 miles long; measured by Enhanced Fujita Scale (EF0–EF5).
Less than once in 100 years (less than 1% chance per year); Massachusetts experiences an average of 1.
increase|low
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Tsunami4.6.3

No additional detail indexed.

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Neighborhood-specific
Waves can be as high as 100 feet (rare); most tsunamis cause sea to rise by a maximum of ten feet; smaller tsunamis with a height of six feet can still easily knock a per...
Approximately once every 39 years along the East Coast; no significant tsunamis have struck the Massachusetts coast
increase|low
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Winter Storms4.5

No additional detail indexed.

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Neighborhood-specific
{'snow_events': 'Heavy snow: 4" or more in 12 hours or less, or 6" or more in 24 hours or less.
Snow events (heavy snow/blizzards): classified as high frequency; can occur more than once in five years (greater than 20% chance of occurring each year).
increase|medium
source