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Stormy weather

posted Sep 14, 2013, 4:47 PM by CCIHC www.hococlimatechange.org
We are overdue for the Big One.

Not an earthquake, but a devastating inland hurricane, according to Rick Schwartz, author of Hurricanes and the Middle Atlantic States. Over the last 400 years, these inland hurricanes have hit this region every 57 or 58 years, and the last such storm, Hazel, hit 59 years ago.

“Hurricane history is repetitive. Events of the past will be events of the future,” said Schwartz, who spoke at the quarterly meeting of the Local Emergency Planning Committee in Ellicott City Friday. He mentioned global warming only in answer to a question and didn’t seem to have factored it into his calculations. “Up to 2 years ago, I would have said there was no evidence” of global warming, he said. But after Irene, Lee, Sandy, the derecho and the snowstorms, “I’m thinking it is beginning to have an effect,” he said.

An inland hurricane typically originates in the Caribbean in September or October, makes landfall as a Category 3 or 4, travels quickly north (faster than 30 mph) and heads in a fairly straight line — straight toward Maryland. The winds, sometimes clocked at 120 mph, are on the east side, rain on the west. “A Category 1 hurricane will do what a category 3 or 4 hurricane will do in Florida,” he said, because our vegetation hasn’t evolved for the higher winds and neither have building codes and other infrastructure. Stoplights in Florida, for example, are built to withstand winds of 100 mph; in this region, they are built to withstand winds of 50 or 60 mph.

Often the “big one” is preceded by a couple other hurricanes that follow a similar straight path north, giving a clue of wind patterns and what might be coming. Schwartz, who researched these storms through diaries, newspaper accounts and other records, said these storms have hit in our area in 1667, 1724, 1769, 1775, 1821, 1878, 1896 and 1954. Because the storms happen so far apart, people tend to forget. “Without the knowledge of hurricane history, it will come as an utter shock,” he said.

A diarist recording the “Great Gust of 1896” wrote of “the abomination of desolation on all sides.” People in Catonsville fled to nearby fields, fearing the imminent collapse of their homes. Two huge gusts from that inland hurricane also destroyed the covered bridge, more than a mile long, in Columbia, Pa. “California has its big earthquakes, [the mid-Atlantic] has its big winds,” he said.

Hurricane Hazel, the last “big one,” brought wind gusts of 98 mph to DC, 84 mph to Baltimore, 90 mph to Annapolis and 112 mph at the Patuxent Naval Air Station. High winds from these storms last for several hours. “Someday, likely soon,” he said, we will have the next Hurricane Hazel.

The region also is affected by other hurricanes, he said, such as Hurricanes Sandy last year and Isabel in 2003. They can bring double-digit rainfall — as with Camille’s 27 inches of rain in 5 hours in Virginia — and tornadoes. They also tend to interact with other weather systems in the area, as Sandy did. Combustible and hazardous materials are a huge threat during these storms. Toxic materials floated from factories into rivers during Agnes, he said. (This is something to keep in mind as the state ponders fracking.)

Hurricanes run in cycles of 25-30 years, he said. We have been in an active cycle since 1995 and probably have 10 more years to go. These cycles can include a quiet year, which might happen this season — although we should not relax yet, he said. Isabel, the closest to an inland hurricane in decades and with wind gusts 50 to 65 mph, left the area with downed trees, power outages and no water in some areas. “This area cannot handle high winds and wet ground,” he said. 

Only two hurricanes have made landfall on the East Coast since 2005. “How much longer can we beat the odds?” he asked. Never have so many people and so much property been at risk in this area. “The next Hurricane Hazel is due, and a period of catch-up seems likely.”

Schwartz also maintains a website: http://www.midatlantichurricanes.com/index.html

--elisabeth hoffman
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