AIR Worldwide: Bertha Now a CAT 2 Hurricane

According to catastrophe risk modeling firm AIR Worldwide, Hurricane Bertha—the first hurricane of the 2008 Atlantic hurricane season—intensified quickly yesterday from Category 1 status in the morning to Category 3 status by the National Hurricane Center’s 5 p.m. advisory. Overnight, however, the storm entered a region of increased wind shear and as of 10 a.m. today, Bertha is now a Category 2 hurricane.

“As of 11:00 a.m. EDT, Bertha was located about 660 miles east northeast of the northern Leeward Islands and 975 miles southeast of Bermuda. Bertha’s maximum sustained winds, which had achieved 120 mph last night, have weakened to 105 mph, with higher gusts,” said Dr. Justin Cox, research scientist & meteorologist at AIR Worldwide. “The National Hurricane Center (NHC) predicts additional weakening over the next 24 hours as the storm continues its northwesterly track.” Forward speed is estimated at nearly 10 mph.

The NHC and the operational forecast models are in better agreement this morning in their assessment that Bertha will recurve well east of Bermuda. However, it is important to recognize that there is uncertainty in these forecasts, and AIR will continue to monitor Bertha’s progress.

Cox continued, “Bertha is a strong early season hurricane. Historically, only five hurricanes have exceeded Bertha’s intensity this early in a hurricane season.”

Hurricane Bertha, Fires Make Presence Known

According to catastrophe risk modeling firm AIR Worldwide, tropical storm Bertha strengthened this morning to become the first hurricane of the 2008 Atlantic hurricane season.

Bertha is currently a Category 3 storm, and will likely maintain this intensity through the night, before weakening slightly on Tuesday. Fluctuations in intensity are likely over the next several days. As of 5 p.m. EST, Bertha was located about 730 miles east of the northern Leeward Islands. Maximum sustained winds are 115 mph, with higher gusts. The storm is moving west northwest at nearly 12 mph.

According to the National Hurricane Center and most of the operational forecast models, Bertha is not likely to pose a threat to the U.S. Gulf or East Coasts.

“There is some disagreement between the forecast models, however, with respect to when and how sharply the track will recurve,” said Dr. Justin Cox, Research Scientist/Meteorologist at AIR Worldwide. “The GFS model suggests that Bermuda may feel the effects of Hurricane Bertha on Saturday. As always, it is important to recognize that there is considerably uncertainty in these forecasts, and AIR is monitoring Bertha's progress closely.”

* Meanwhile, in northern and central California, firefighters have contained about 1,400 of the nearly 1,800 wildfires burning since June 20th.

These fires—ignited by lightning and fueled by conditions in the state's driest spring since 1894—have burned close to 600,000 acres. They continue to threaten some 10,500 homes and more than 400 commercial properties.

Firefighters are making some progress. Yesterday, crews constructed a fire line on the eastern side of the Gap Fire, a particularly large and fast-moving inferno in the Los Padres National Forest. The Gap Fire expanded dramatically between Tuesday, July 1, and Wednesday, July 2, growing from 200 acres to more than 2,400. By Sunday, it had spread across 9,924 acres of California land and was only 30% contained. It continues to threaten some 2,800 residences in the coastal city of Goleta, northwest of Santa Barbara.

“The Gap Fire has been fanned by so-called "Sundowner" winds—Santa Barbara's equivalent of the Santa Ana winds,” said Scott Stransky, research analyst at AIR Worldwide. “This type of Foehn wind is much more common in the fall and winter, but it is not out of the ordinary to see it fuel fires in the summer months. The Sycamore Canyon (1977), Wheeler (1985), and Painted Cave (1990) Fires all occurred during Sundowner conditions in summer months.”

Another noteworthy fire—the Basin Fire—continues to ravage land near the famed resort of Big Sur, in Monterey County. On July 1rst, the fire intensified and jumped a fire line set up to protect the town. The following day, some 1,500 residents in the area were ordered to evacuate. As of Sunday, the Basin Fire had consumed 74,985 acres and destroyed 23 residences and 23 outbuildings. It was 11% contained—up from 3% at the end of last week. The Basin Fire continues to threaten 2,500 homes in Big Sur Valley.

“Typically, between 5,000 and 10,000 fires burn each year in California, but lightning strikes—the source of this summer's flames—usually account for only about 10% of fire ignitions in the state,” continued Stransky. “Lack of rain in 2008 left fuels in the area very dry. Also, many of the fires started by lightning were and are burning in chaparral, considered one of the most dangerous fuels in the wilderness. Exacerbating matters, the jet stream shifted far to the north, preventing storms from delivering rain, and although cool air was moving in from the Pacific to aid firefighting efforts earlier today, no rain is expected in the near future.”