Hurricane Ida makes landfall in Louisiana: the fifth largest hurricane to hit the continental United States in history-the United States

According to foreign media reports. Exactly 16 years after Hurricane Katrina made landfall, another major hurricane made landfall in southern Louisiana. At around noon on August 29, local time, Hurricane Ida made landfall near the Port of Fourchon at a pressure of 930 millibars and sustained wind speeds of 150 miles (240 kilometers) per hour.Preliminary reports indicate that it is the fifth largest hurricane (based on wind speed) ever to make landfall on the continental United States.

At 2:50 am local time on August 30th, the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite obtained a night view of Hurricane Ida. On the morning of August 29, the National Oceanic and Atmospheric Administration (NOAA) GOES-16 satellite obtained animation data of the menacing “Hurricane Eye” approaching the coast.

In the last 24 hours before landing, the center pressure of the storm dropped from 985 mbar to 929 mbar, and the wind speed rapidly increased from 85 to 150 miles per hour. According to the National Hurricane Center, a storm experiences a “rapid increase” when the wind speed increases by at least 35 mph in a 24-hour period. Part of the increase is due to the hot surface water in the Gulf of Mexico in summer, about 30-31 degrees Celsius.

The above animation shows the evolution of the “Ada” wind field between August 27-30, 2021. The strongest winds appear as bright yellow to white; the milder winds are orange and bright purple shades. Atmospheric data has been run through the Goddard Earth Observation System Model-5 (GEOS-5), which is a data assimilation model used by NASA scientists to analyze global weather phenomena. The GEOS model ingests wind data from more than 30 sources, including ships, buoys, radio monitors, drip meters, airplanes, and satellites. The output of the model is performed on a grid of 0.25 to 0.3 degrees, so it may not be able to capture the peak gusts and extreme conditions measured by a single instrument on the surface.

Scott Braun, a scientist at NASA’s Goddard Space Flight Center who specializes in hurricanes, said: “For me, the most striking aspect of Hurricane Ida is its rapid intensification before landing. This storm is incompatible with Hurricane Opal and Katrina. Hurricanes are very similar because they experience rapid intensification in a deep warm water area or vortex known as the Gulf Circulation. In addition to providing warm water as fuel, this vortex also prevents colder water from mixing to the surface. This This kind of cooling usually causes the storm to weaken, or at least stop strengthening. Both Opal and Katrina weakened before making landfall, reducing the impact of the storm to a certain extent, although they were clearly still bad. Hurricane Ida made landfall. , The near-shore weakening did not really happen.”

Hurricane Ida caused dangerous storm surges on the coasts of Louisiana and Mississippi. Weather stations and media reports pointed out that 3 to 9 feet (1 to 3 meters) storm surges occurred in Grande Isle, Shell Beach, Lafitte, Barataria, Fourchon Port and other places. The Port of Fourchon is a major commercial and industrial center in the United States, especially for oil and gas.

For most of August 29, the storm lingered in southern Louisiana, bringing heavy rainfall that caused flooding before moving north and east into Mississippi and Alabama on August 30. The slow pace of the storm may amplify the severe damage to the electricity and drinking water infrastructure, while delaying the start of cleanup work. According to reports, by noon on August 30, more than 1 million households in Louisiana had power outages. Another 100,000 households in Mississippi were out of power, and 12,000 in Alabama. The map above shows the distribution of outages compiled by PowerOutage.US based on publicly available data sources.

“I’m interested in the translation speed of Ada after landing,” said Su Hui, who studies hurricanes at NASA’s Jet Propulsion Laboratory. “There have been studies on how global warming caused tropical cyclones to slow down, which could lead to greater flooding and inundation losses. (For example, Hurricanes Harvey and Dorian.) Due to the quality of historical data, there is still debate. , But climate model simulations show that the translational speed of hurricanes will decrease with global warming.”