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“It’s not common to measure rainfall in feet,” says meteorologist David Eversole. Usually much smaller units are sufficient. But Hurricane “Sally” blew the scale. The hurricane brought record rains on its way. Only in Pensacola, Florida, two feet of precipitation fell, the equivalent of 61 centimeters.
Early Wednesday morning local time, “Sally” touched down at speeds of up to 165 kilometers per hour as a Level 2 of 5 hurricane near the city of Gulf Shores, Alabama. According to initial reports, at least one person is said to have died, half a million homes were without power, and damage is estimated at $ 2 to $ 3 billion.
As the southeastern United States floods, the largest wildfire in California history is raging on the West Coast and spreading. Almost nowhere else in the world was air quality as bad as in some parts of California these days; Schools, parks, beaches had to be closed. The soot particles created by the fire even made the sky over Germany appear milky.
On the one hand fire, on the other hand water: the United States is caught between two natural disasters that could hardly be more contradictory, but that are part of the same global development: climate change creates or worsens the conditions for such an extreme climate . And the worst could still be ahead of the United States.
The hot, dry, fire-fueling Santa Ana winds, also known as Devil’s Winds, typically hit California in late fall and winter. And the hurricane season in the Atlantic doesn’t end until late November. (Read the SPIEGEL series on fires here).
When climate change and “La Niña” collide
The next storm is already on the horizon. According to the National Hurricane Center (NHC), there is a 70 percent chance that the next preliminary stage of a hurricane will develop over the southwestern Gulf of Mexico in the next two days. Still, meteorologists expect a particularly violent hurricane season.
Cyclones can only emerge if the water surface temperature is above 26 degrees, and this year the water in the North Atlantic and the Gulf of Mexico is above average. In western Florida, temperatures hovered around 30 degrees. One of the reasons for this is the climate crisis. Much of the Atlantic and the air masses above have warmed more strongly than in recent decades at this time of year.
This mixed situation not only favors hurricanes. In hot air, more water can evaporate, it rains more. At the same time, the warmer water expands and the sea level rises. Forecasters are also expecting a “La Niña” event in the fall, which will encourage the development of hurricanes.
For the evaluation of a cyclone, two speeds are decisive:
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The first is that Air rotationIt reaches between 119 and 345 kilometers per hour. The lowest value is the threshold from which one speaks of a category one hurricane, the highest the previous record, set in 2015 by Cyclone Patricia on the Pacific coast of Mexico. The higher this speed, the greater the damage from the winds.
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The second speed describes the Movement of the entire storm system, that is, how fast a hurricane moves. The speed is usually between ten and 40 kilometers per hour. The lower this value, the longer it rains in a place due to the storm.
Climate experts estimate that climate change will make hurricanes wetter and slower to move, and therefore more dangerous. The speed of the storms decreased by an average of ten percent between 1949 and 2019. The phenomenon was also evident during Hurricane “Sally.” The cyclone sometimes only moved at about two miles per hour; the average pedestrian walks at a similar speed. For comparison: Hurricane “Paulette” passed through Bermuda this week at 25 miles per hour.
Meteorologists expect record hurricane season
Low speed in particular leads to heavy rainfall. For a full day, Sally rained down on the coastal communities of Florida, Alabama and Mississippi. Forecasters also had a headache from “Sally’s” inconsistent heading and had to update forecasts multiple times on which regions would be particularly affected.
Meanwhile, “Sally” is no longer considered a hurricane, but a tropical storm. There is no reason for relief. Hurricane “Harvey” also fell into the tropical storm category in 2017 when it moved toward Houston, Texas. For five days it stopped completely, heavy rains caused the lakes to overflow. Entire neighborhoods were under water. 93 people died, most of them living in areas where floods are not normally expected.
Forecasters expect 24 tropical cyclones in November, double the usual. Experts may even run out of default names for cyclones. At the moment there are only 21 names on the list. (Here you can read more about it).
“I wish science would agree with you”
On Monday, five active tropical cyclones were simultaneously in the Atlantic, this has not happened in 50 years. It is only the second such storm since meteorological records began. Forecasts for this season are close to the previous record in 2005. At that time, Hurricane “Katrina” devastated New Orleans and the southern United States.
Natural disasters hit the country at the worst possible time. In the crown crisis in particular, it is fatal when tens of thousands of people have to wait in emergency shelters. Furthermore, the United States is governed by a president who questions the climate crisis.
Donald Trump had repeatedly dismissed climate change as a “hoax” or an invention by China, which for the first time in its 175-year history led the US scientific journal “Scientific American” to issue a recommendation for the upcoming presidential elections, against Trump.
Trump recently tried to downplay the fires during a brief visit to California. “It will start to get cold, just watch,” promised the president. California Secretary of the Environment Wade Crowfoot responded, “I wish science would agree with you.”
Editor’s Note: An earlier version said the storm had also passed over California. We fixed the bug.
