Another Record

Dr. Jeff Masters noted another record for hurricanes this year:

Lorenzo sets another rapid intensification record for 2007
Hurricane Lorenzo hit Mexico’s Veracruz coast near Tuxpan early Friday morning. The storm’s heavy rains have triggered mudslides blamed for at least four deaths. Lorenzo has tied the Atlantic record for fastest intensification from a tropical depression to a Category 1 hurricane–twelve hours. Hurricane Blanche of 1969 was the only other storm on record that intensified from a tropical depression to a Category 1 hurricane in just 12 hours. Hurricane Ethel of 1960 may have done so faster, though. Ethel strengthened from a 45-mph tropical storm to a 85 mph Category 1 hurricane in just 6 hours. We don’t know when Ethel started as a tropical depression, since this was before the satellite era.

Reliable record keeping of intensification rates of Atlantic hurricanes began in 1970, when regular satellite coverage became available. Since 1970, Hurricane Humberto of 2007 holds the record for fastest intensification from first advisory issued to hurricane strength–18 hours. (Actually, Humberto did the feat in 14 1/4 hours, but this will get rounded off to 18 hours in the final data base, which stores points every six hours). There have been six storms that accomplished the feat in 24 hours.

Since 1970, Hurricane Felix of 2007 holds the record for fastest intensification from the first advisory to a Category 5 hurricane. It took Felix just 54 hours to accomplish the feat. Hurricane Camille of 1969 also took 54 hours to do so, but the first advisory put Camille as a 60 mph tropical storm. It is likely that Camille would have been classified as a tropical depression earlier had reliable satellite imagery been available.

Is it a statistical fluke that we’ve had three record-speed intensifying hurricanes this year? It could be. Our reliable data records only go back to 1970, and there may have been periods in the past with similar events. No scientist has published a paper linking rapid hurricane intensification rates with global warming. However, three record-speed intensifying hurricanes in one season certainly raises questions, and is very odd.

We haven’t had many storms hit the US, but things are certainly not as quiet as people might think.