Pennsylvania Emergency Preparedness Guide

Pennsylvania's Disaster Landscape

Pennsylvania's geography creates a unique hazard profile. The state stretches from the Lake Erie shore through the Appalachian Mountains to the Delaware River valley—300 miles of diverse terrain where different hazards dominate different regions. What unifies the state is water: Pennsylvania has more miles of rivers and streams than any state except Alaska, making flooding the dominant natural hazard.

The Susquehanna River—the largest river on the East Coast draining into the Atlantic—flows through the heart of Pennsylvania. Its basin covers half the state and includes Harrisburg, Wilkes-Barre, and numerous smaller communities built in flood-prone valleys. When tropical moisture meets Appalachian terrain, catastrophic flooding results.

Beyond flooding, Pennsylvania faces the full spectrum of northeastern weather hazards. Nor'easters bury the state under heavy snow. Lake-effect bands hammer the northwest corner. Ice storms fell trees and power lines. Severe thunderstorms spawn damaging winds, large hail, and occasional tornadoes. Summer heat waves stress urban populations. Pennsylvania preparedness requires readiness for multiple, overlapping hazards.

Flooding: Pennsylvania's #1 Hazard

Flooding causes more deaths, more damage, and more disaster declarations in Pennsylvania than any other hazard. The combination of extensive river systems, steep terrain, aging dam infrastructure, and high population density in valley communities creates persistent flood risk.

Historic Pennsylvania Floods

The Johnstown Flood (1889) killed 2,209 people when the South Fork Dam failed, sending a 40-foot wall of water through the city. This remains one of the deadliest disasters in American history and led to improved dam safety standards.

Hurricane Agnes (1972) caused catastrophic flooding across Pennsylvania. The Susquehanna crested at record levels, devastating Wilkes-Barre, Harrisburg, and dozens of communities. Fifty people died and damages exceeded $3 billion (1972 dollars). Agnes remains the benchmark for Pennsylvania flood planning.

Tropical Storm Lee (2011) combined with the remnants of Hurricane Irene to cause widespread flooding. The Susquehanna again reached record levels in some locations, forcing mass evacuations.

Hurricane Ida remnants (2021) demonstrated that flood devastation continues. Philadelphia area communities experienced deadly flash flooding, and the storm spawned a tornado outbreak.

Types of Pennsylvania Flooding

River flooding occurs when major rivers like the Susquehanna, Delaware, Ohio, and Allegheny overflow their banks. This type develops over hours to days, providing warning time but affecting large areas for extended periods.

Flash flooding strikes with little warning when intense rainfall overwhelms streams, urban drainage, and small watersheds. Pennsylvania's mountain terrain channels water rapidly into valleys. Flash floods can occur miles from where rain falls.

Dam failure flooding remains a concern. Pennsylvania has over 3,000 dams, many built decades ago. While major dams are closely monitored, smaller "high hazard" dams pose risks to downstream communities.

Urban flooding affects Philadelphia, Pittsburgh, and other cities where impervious surfaces prevent water absorption. Combined sewer systems can overflow during heavy rain, and low-lying areas flood repeatedly.

Flood Preparation

• Know your flood zone: Check FEMA flood maps at FloodSmart.gov
• Purchase flood insurance: Standard homeowners doesn't cover floods; there's a 30-day waiting period
• Elevate critical items: Utilities, important documents, valuables
• Know evacuation routes: Plan routes that avoid flood-prone roads
• Never drive through floodwater: Turn Around, Don't Drown
• Sign up for alerts: PA alerts system, local emergency notifications

Winter Weather: Nor'easters, Ice, and Lake Effect

Pennsylvania winters vary dramatically across the state. Erie receives more snow than Denver, while Philadelphia experiences relatively mild winters punctuated by major Nor'easters. Ice storms threaten the entire state.

Nor'easters

These powerful storms form along the East Coast and can bury Pennsylvania under feet of snow:

• Blizzard of 1996: 30+ inches across much of eastern PA
• February 2010: "Snowmageddon" dropped 20+ inches on Philadelphia
• January 2016: 22-30 inches paralyzed the state

Nor'easters bring not just snow but high winds, coastal flooding along the Delaware River, and transportation shutdowns lasting days.

Lake-Effect Snow

Northwestern Pennsylvania, particularly Erie County, receives intense lake-effect snow from Lake Erie:

• Annual snowfall: Erie averages 100+ inches
• Intensity: 3-4 inches per hour possible in heavy bands
• Localized: Heavy snow can fall in one location while nearby areas receive nothing
• Season: November through February, peaking before lake freeze

The infamous Thanksgiving 2014 lake-effect event buried parts of the Erie region under 6+ feet of snow in a few days.

Ice Storms

Ice storms cause the most prolonged power outages in Pennsylvania. Heavy ice accumulation brings down trees and power lines, sometimes leaving communities without power for a week or more:

• Half-inch ice accumulation can cause major damage
• Trees weakened by previous storms are particularly vulnerable
• Mountainous areas recover more slowly due to access challenges
• Rural areas may wait days for power restoration

Winter Preparation

• Alternative heat: Space heaters, wood stove, or generator capability
• Pipe protection: Insulate exposed pipes, know main shutoff
• Vehicle supplies: Winter emergency kit with blankets, shovel, sand
• Carbon monoxide detection: Essential when using backup heating
• 3-7 day supplies: Food, water, medications, batteries
• Snow removal equipment: Quality snow shovel, ice melt

Tropical Storm Remnants: Pennsylvania's Hidden Hurricane Threat

While hurricanes don't make direct landfall in Pennsylvania, the state sits directly in the path of tropical moisture racing up the East Coast. When this moisture combines with Pennsylvania's mountain terrain, catastrophic flooding results.

How Tropical Storms Affect Pennsylvania

1. Heavy rainfall: Tropical moisture can produce 10+ inches of rain across wide areas
2. Orographic enhancement: Mountains force air upward, squeezing out additional rainfall
3. Saturated ground: Antecedent rainfall means ground can't absorb more water
4. River cresting: Major rivers continue rising for days after rain ends
5. Tornado outbreaks: Remnant tropical systems can spawn multiple tornadoes

Preparing for Tropical Remnants

• Monitor tropical systems a week or more in advance
• Know your flood risk even if you're not in a "flood zone"
• Have evacuation supplies ready during hurricane season
• Prepare for extended power outages
• Don't assume "just a tropical storm" means safety

Severe Thunderstorms and Tornadoes

Pennsylvania experiences severe thunderstorms from spring through fall. While not as tornado-prone as Midwest states, Pennsylvania averages 15-20 tornadoes annually, and severe wind events can cause tornado-like damage.

Pennsylvania Tornado Characteristics

• Season: April through August, with June-July peak
• Warning challenges: Hilly terrain hides tornadoes; heavy tree cover reduces visibility
• Tropical connections: Remnant tropical systems spawn tornado outbreaks
• Supercells: Classic rotating supercells can develop, particularly in western PA

Damaging Winds

Straight-line winds cause more damage than tornadoes in most years:

• Derechos (long-lived windstorms) periodically sweep across the state
• Microbursts can produce 100+ mph localized wind
• Gust fronts ahead of thunderstorms can topple trees

Large Hail

Pennsylvania supercells produce hail capable of damaging vehicles, roofs, and crops. Hailstones larger than golf balls occur multiple times each year.

Severe Weather Safety

• NOAA weather radio for warnings (especially important at night)
• Know your safe room location (basement or interior room)
• Have multiple ways to receive warnings (radio, phone, sirens)
• Don't wait for tornado warning to seek shelter if storm looks threatening

Extreme Heat: Urban Pennsylvania's Growing Threat

Heat waves increasingly threaten Pennsylvania's urban areas, particularly Philadelphia and Pittsburgh. Urban heat islands can make cities 10-15°F hotter than surrounding areas.

Heat Vulnerability

• Philadelphia: Dense urban core, older housing stock, many homes without central AC
• Pittsburgh: Valley terrain traps heat and pollution
• Elderly populations: High proportion of seniors in affected areas
• Power grid stress: Peak AC demand can cause outages when cooling is most needed

Heat Safety

• Know cooling center locations in your community
• Check on elderly relatives and neighbors
• Stay hydrated before feeling thirsty
• Know heat exhaustion vs. heat stroke symptoms
• Never leave children or pets in vehicles

Regional Preparedness Priorities

Philadelphia Region

Primary threats: Nor'easters, extreme heat, flash flooding, tropical remnants

• Heat wave preparedness with cooling plans
• Flash flood awareness in urban areas
• Winter storm supplies for Nor'easters
• Apartment/rowhouse emergency planning
• Know evacuation routes for Schuylkill/Delaware river flooding

Pittsburgh Region

Primary threats: River flooding, severe storms, winter weather

• Three Rivers confluence creates flood risk
• Steep terrain increases flash flood danger
• Lake-effect influence possible in western suburbs
• Urban heat island effects in valleys

Central Pennsylvania (Harrisburg, State College)

Primary threats: Flooding, winter storms, severe weather

• Susquehanna River flood zone awareness
• Mountain snow can vary dramatically by elevation
• Tornado awareness during severe weather
• Rural self-sufficiency for extended outages

Northeastern Pennsylvania (Scranton, Wilkes-Barre)

Primary threats: Flooding, winter storms, tropical remnants

• Historic flood zone (Agnes devastation)
• Heavy Nor'easter snowfall totals
• Mining legacy creates some subsidence risk
• Levee system awareness along Susquehanna

Northwestern Pennsylvania (Erie region)

Primary threats: Lake-effect snow, winter storms, lake flooding

• Extreme winter preparedness essential
• Lake Erie seiche (wind-driven flooding) awareness
• Extensive snow removal capability needed
• Extended self-sufficiency supplies for isolation

Rural/Mountain Pennsylvania

Primary threats: Flooding, ice storms, extended isolation

• Extended self-sufficiency (7+ days) for power outages
• Alternative heating critical
• Flash flood evacuation awareness
• Communication plans when cell service is spotty

Pennsylvania Emergency Resources

• Pennsylvania Emergency Management Agency: pema.pa.gov
• PA 511 (road conditions): 511pa.com
• Philadelphia OEM: phila.gov/oem
• NWS Philadelphia: weather.gov/phi
• NWS Pittsburgh: weather.gov/pbz
• NWS State College: weather.gov/ctp
• Susquehanna River Basin Commission: srbc.net

Pennsylvania Emergency Kit Essentials

Year-Round Supplies

• Water: 1 gallon per person per day for 7 days (flooding can contaminate water supply)
• Non-perishable food for 7 days
• NOAA weather radio with battery backup
• Flashlights with extra batteries
• First aid kit
• Prescription medications (7-day supply minimum)
• Cash (ATMs fail during power outages)
• Phone chargers (battery-powered and vehicle)
• Important documents in waterproof container
• Copies of insurance policies

Winter Additions

• Alternative heating source with fuel
• Extra blankets and warm clothing
• Carbon monoxide detectors with battery backup
• Ice melt and quality snow shovel
• Vehicle emergency kit (blankets, shovel, sand, flares)

Flood Season Additions

• Waterproof document container
• Evacuation "go bag" packed and accessible
• Inflatable mattress or cot (for evacuation shelter)
• Battery backup sump pump (if applicable)