Why a Category 1 Hurricane Florence is still so dangerous

WILMINGTON, N.C. (KXAN) — Hurricane Florence made landfall over North Carolina Friday morning as a Category 1 storm. Despite dropping in wind intensity over the past few days, it still could bring devastating flooding to the area. 

A Category 1 hurricane has maximum sustained wind speeds of 74 to 95 miles per hour. As of 6 a.m. Friday, Florence had a wind speed of 90 mph, which, according to the National Hurricane Center, are still enough to damage roofs, shingles, siding and gutters. Tree branches can snap and trees can topple, and there can be extensive damage to power lines and poles.

However, the Saffir-Simpson Hurricane Wind Scale (where we get categories 1-5) only measures wind. In Florence’s case, the storm is huge, which increases the effect.

“A significant category 1 storm, significant even though it’s a weaker hurricane if you want to call it that, partially because the wind field is huge,” said KXAN Meteorologist David Yeomans, pointing to an area that stretches from South Carolina to Virginia. “When you have a wind field that is literally this big of tropical storm or greater winds, that makes storm surge. Flooding impacts more reminiscent of a category 3 or 4 storm.”

Hurricane Sandy made landfall in the northeast in 2012 after weakening from a Category 1 hurricane to a post-tropical cyclone, according to the National Weather Service. 

“The track of Sandy resulted in a worse case scenario for storm surge for coastal regions from New Jersey north to Connecticut including New York City and Long Island,” the NWS wrote in a report. “Unfortunately, the storm surge occurred near the time of high tide along the Atlantic Coast. This contributed to record tide levels.”

Sandy was the fourth-most costly tropical cyclone in U.S. history, after Katrina, Harvey and Maria, according to the National Oceanic and Atmospheric Administration.