Over 1 million people live in Delaware. Many of these people have experienced natural disasters in the state firsthand. However, many don’t realize just how many different natural disasters can occur in the state or how the risk for some disasters is increasing.
Here we will go over what natural disasters occur in Delaware, the worst natural disasters to hit the state since 2000, and what can be done to prepare.
Is Delaware At Risk of Natural Disasters?
Delaware has a very low risk of natural disasters compared to the rest of the country. Excluding COVID, Delaware has only had 10 major disaster declarations since 2000. There were 19 disaster events affecting Delaware, which caused more than $1 billion in damages. However, natural disasters can still occur in Delaware, and all residents should be prepared.
Worst Natural Disasters in Delaware Since 2000
Since 2000, the worst natural disasters in Delaware in terms of damage and death toll have been hurricanes. The state can also sometimes get severe storms, winter storms, droughts, heat waves, and floods.
Worst Natural Disasters in Delaware By Cost (Since 2000)
- Hurricane Sandy 2012: $83.9 billion
- Hurricane Ida 2021: $80.2 billion
- Hurricane Ivan 2004: $32.2 billion
- 2002 Drought: $15.1 billion
- Hurricane Jeanne 2004: $11.8 billion
Worst Natural Disasters in Delaware By Deaths (Since 2000)
- Hurricane Sandy 2012: 159 deaths
- Hurricane Ida 2021: 96 deaths
- Hurricane Ivan 2004: 57 deaths
- Hurricane Isabel 2003: 55 deaths
- April 2020 Tornado Outbreak: 35 deaths
*Cost and death tolls are for the entire disaster, including in other states affected.
What Natural Disasters Occur in Delaware?
No hurricane has ever directly hit Delaware. However, many hurricanes have landed in nearby states. These hurricanes can cause lots of damage to Delaware from high winds, heavy rains, and flooding.
During hurricanes Sandy in Delaware, 45 thousand people were left without power, and shoreline flooding caused massive damage. Hurricanes Isabel and Ida were also particularly destructive and caused power outages, flooding, and forced evacuations.
Hurricane fatalities in Delaware are very rare but do sometimes happen. For example, during tropical storm Isaias, a woman died after being hit by a tree branch.
For more, read: How to Prepare for a Hurricane
2. Winter Storms and Freeze Events
While hurricanes can cause vast amounts of damage in Delaware, winter storms are most likely to cause damage in the state. The state has had to declare disaster twice because of winter storms: once in February 2010 and in January 2016.
Even when winter storms in Delaware aren’t bad enough to merit disaster declarations, they can still cause massive amounts of damage. Strong winds damage property and power lines. As snow melts, it causes flooding.
The winter storms can be deadly. When power outages occur, people are at risk of carbon monoxide poisoning from incorrectly using generators or blocked tailpipes on their vehicles. Vehicle accidents are common and cause more fatalities than any other natural disaster in the state.
To be prepared, Delawareans should have a winter car emergency kit and an emergency heater and ensure they know how to use it indoors safely.
Flooding disasters are common in Delaware. Currently, approximately 9.4% of properties in Delaware are at substantial risk of flooding. By 2050, this number will increase to 11.3%. Even more properties are at moderate risk of flooding in the state. In some areas of Delaware, such as Bethany Beach, almost all properties are at risk of flooding.
Which Areas of Delaware Are Most At-Risk of Flooding?
The following municipalities are at the most risk of flooding, based on the percentage of properties likely to experience flooding based on 2020 calculations.
- Bethany Beach: 97%
- Lewes: 47%
- Ocean View: 38%
- Millsboro: 23%
- Seaford: 20%
- New Castle: 20%
- Georgetown: 12%
- Dover: 9%
- Milford: 8%
Because of climate change, the risk of flooding is increasing in most areas of Delaware. For example, by 2050, an estimated 12% of all properties in Milford will be at risk.
Worst Flood Events in Delaware’s Recent History
Since 2000, Delaware has declared disaster twice due to flooding. One of the flood incidents occurred in June 2006 when heavy rains caused the Delaware River Basin to flood. Most of the damage was in New Jersey, but Delaware was also affected. The other event was in January 2016, when winter weather caused a storm surge in the coastal areas.
In addition to river basin and winter flooding, Delaware has also experienced severe flooding from hurricanes. During hurricane Isabel in 2003, over 11 thousand properties were flooded. Hurricane Irene in 2009 flooded over 9 thousand properties.
Also read: How to Prepare for Flood Disasters
While Delaware isn’t known for tornadoes, they do occur in the state. On average, Delaware has just one tornado per year. None of these tornadoes have been higher than EF2 on the Enhanced Fujita Scale.
The worst tornado in recent history in Delaware was spawned from tropical storm Isaias. That tornado had a nearly 30 miles long path from Dover to Middletown. The winds reached 96 miles per hour and caused roofs to blow off and damage from flying debris. In 2004, hurricane Jeanne also spawned a tornado which caused damage in its 5-mile path.
For more, read: Where to Go during a Tornado
Compared to states like California and Alaska, Delaware is low-risk for earthquakes. However, earthquakes do sometimes happen in Delaware. There have been over 550 earthquakes within 150 miles of Delaware since 1677. Because of the risk, FEMA and the USGS reclassified Delaware from “low” to “moderate” seismic risk in 1997.
The good news is that most Delaware earthquakes are very weak. The largest recorded earthquake in Delaware was a magnitude 4.1 earthquake in Dover in 2017. Even this earthquake didn’t cause any serious damage.
Despite the low risk, Delaware residents should still follow basic earthquake safety precautions, such as anchoring heavy items to walls.
Sinkholes occur when rock layers under the ground erode, causing a hole. Because of the types of rocks found in Delaware, some parts of the state are particularly vulnerable to sinkhole formation. These include Hockessin and the Pleasant Hill areas in northern Delaware. Sinkholes can suddenly and catastrophically collapse, so residents should take them seriously.