20 years after Hurricane Katrina, scientists warn about what could be an even more destructive hurricane season. When it hit Plaquemines Parish, Louisiana, Hurricane Katrina cost more than $186 billion and caused 1,833 fatalities. It was the most devastating hurricane to date.
Now, hurricane relief programs have changed, but so has Earth’s climate.
Hurricanes are intensifying more than ever before, putting coastal communities like Miami at increased risk of flooding and damages. Residents need to be prepared for strong, lingering wind and rain effects as temperatures and sea levels continue rising.
Global temperatures have risen 2 degrees Fahrenheit in the last 150 years, and are expected to raise another degree by 2050. What looks like a small change will have a large impact. For hurricanes, rising temperatures result in more evaporation and humidity and the added energy increases rainfall. These factors lead to more intense storms and severe flash flooding, giving residents less time to evacuate.
“While hurricanes are classified by their sustained maximum wind speeds, the deadliest impacts often come from water, not wind,” said Dr. Lisa Murphy Goes, a senior lecturer for the Department of Atmospheric Sciences at the Rosenstiel School of Marine, Atmospheric & Earth Sciences.. “In recent years, the majority of hurricane-related fatalities have been caused by flooding from intense rainfall.”
Most of the fatalities during Hurricane Katrina were caused by the prolonged floods. 40% of victims died by drowning.
Changing sea levels could increase the percentage.
Sea levels in Florida have risen more than 4 inches since the 1990s and flooding has continued to worsen in coastal communities. At the peak of hurricane season these communities face another problem: storm surges. Storm surges are walls of water pushed past the sea level by hurricane winds.
“Today’s hurricanes have the potential to push storm surge further inland than was possible just a few decades ago, increasing risks to coastal communities,” said Dr. Murphy Goes.
The damage from floods and storm surges is exacerbated by rapid intensification. This phenomenon occurs when a hurricane’s winds increase by at least 35 mph within 24 hours. Changes to wind speed often happen before landfall and start to decrease afterwards.
While rapid intensification is not a new concept, it is occurring in storms more frequently than ever before.
“The factors that fuel this process — such as a warm ocean and moist atmosphere — have both been amplified by human-caused climate change, making rapid intensification more likely today than in the past,” said Dr. Murphy Goes.
This August, Hurricane Erin changed from a Category 1 Hurricane with winds of 75 mph to a Category 5 with almost 160 mph in just more than 24 hours.
Erin was the fastest hurricane to reach Category 5 outside of the Caribbean Sea and the Gulf of Mexico, according to a blog post from Dr. Brian McNoldy, a senior research assistant at the University of Miami.
Despite the rate at which Hurricanes intensify, an unknown mechanism related to changes in the atmosphere is making their movement speeds decrease.
The last hurricane to make landfall in Florida, Hurricane Milton, took four days after being announced as a tropical depression to reach Siesta Key, Florida. 48 more hours than Hurricane Katrina.
As climate change makes tropical storms more unpredictable, stronger hurricanes could hit areas unprepared for these events. Hurricane prevention techniques take time. Many do not even know where to start.
Due to increased risk, residents of coastal areas, such as those in Miami, should prepare for intense hurricanes in numerous ways. The first step in preparedness is knowing when hurricane season is: June 1 through Nov. 30.
“Make sure your emergency kit includes extra water and nonperishable food, and have an evacuation plan ready in case you need to leave quickly,” said Dr. Murphy Goes.
The University of Miami also has a website on hurricane preparedness to educate its community.
Inside it, there is a detailed guide on emergency kit essentials and training exercises. Be ready to evacuate with these essential items if a storm intensifies or changes course.
Dr. Murphy Goes recommends to “stay informed through trusted scientific sources such as the National Hurricane Center (NHC) and your local National Weather Service (NWS).”