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Hurricane "Sally" confirms what climate experts have predicted
Photo: GOES-16 / NOAA / NASA
"It is not common to measure rain in feet," says meteorologist David Eversole.
Usually much smaller units are sufficient.
But hurricane "Sally" blew the scale.
The cyclone caused record rainfall on its way across California.
In Pensacola (Florida) alone, two feet of precipitation fell, the equivalent of 61 centimeters.
Early Wednesday morning local time "Sally" hit land 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 houses were without electricity, and the damage is estimated at two to three billion dollars.
While the east coast of the USA is flooding, the largest forest fire in the history of California is raging on the west coast - and it is spreading.
Almost nowhere else in the world was the air quality as bad as it was in 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.
Fire on one side, water on the other - the USA is caught between two natural disasters that could hardly be more contradictory, but which are part of the same global development: Climate change creates or aggravates the conditions for such extreme weather conditions.
And the worst could still be ahead of the US.
The dry, warm, fire-fueling Santa Ana winds, also known as the Devil's Winds, usually hit California in late autumn and winter.
And the Atlantic hurricane season doesn't end until the end of November.
(Read the SPIEGEL series on the 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 brew over the southwestern Gulf of Mexico in the next two days.
Meteorologists are expecting a particularly violent hurricane season anyway.
The cyclones can only occur if the surface temperature of the water is above 26 degrees - and this year the water in the northern Atlantic and the Gulf of Mexico is above average.
West of Florida the temperatures were around 30 degrees.
One reason for this is the climate crisis.
Large parts of the Atlantic and the overlying air masses have heated up more strongly than in previous decades at this time of the year.
This mixed situation not only favors hurricanes.
In warm air, more water can evaporate, it rains more.
At the same time, warmer water expands and the sea level rises.
Meteorologists also expect a "La Niña" event in the fall, which will encourage hurricanes to develop.
For the assessment of a cyclone two speeds are decisive:
The first is the
rotation of the air
, it reaches between 119 and 345 kilometers per hour.
The lower value is the threshold from which one speaks of a category one hurricane, the upper the previous record, set in 2015 by cyclone Patricia off the Pacific coast of Mexico.
The higher this speed, the greater the damage from the winds.
The second speed describes the
movement of the entire storm system
, i.e. how fast a hurricane moves.
The speed is usually between 10 and 40 kilometers per hour.
The lower this value, the longer it rains on one spot from the storm.
Climate experts anticipate that climate change will make hurricanes wetter and slower to move - making them more dangerous.
The speed of storms fell by an average of ten percent between 1949 and 2019.
The phenomenon was also evident during Hurricane "Sally".
The cyclone sometimes only crawled forward at about three kilometers per hour - the average pedestrian walks at a similar speed.
For comparison: Hurricane "Paulette" passed Bermuda this week at 40 kilometers per hour.
Meteorologists expect a record hurricane season
The slow speed in particular leads to heavy precipitation.
For a full day, Sally rained on coastal communities in Florida, Alabama, and Mississippi.
The meteorologists also had a headache for "Sally's" inconsistent rolling course. They had to update forecasts several times as to which regions will 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 towards Houston, Texas.
For five days he came to a complete stop, the heavy rains caused lakes to overflow.
Entire neighborhoods were under water.
93 people were killed, most of them lived in areas where flooding is not normally to be expected.
Meteorologists expect 24 tropical cyclones by November - twice as many as usual.
The experts may even run out of pre-determined names for the 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 storm jam of its kind since weather records began.
The forecasts for this season come close to the previous record year 2005.
At that time, Hurricane Katrina devastated New Orleans and the southern United States.
The natural disasters hit the country at the worst possible time.
In the corona crisis in particular, it is fatal when tens of thousands of people have to wait in emergency shelters.
In addition, the US is ruled 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 science magazine "Scientific American" to issue a recommendation for the upcoming presidential election - against Trump.
Just recently, Trump tried to downplay the fires during a short visit to California.
"It will start to get cooler, just watch," the President promised.
California Secretary of the Environment, Wade Crowfoot, countered, "I wish science would agree with you."
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