Right now, Hurricane Matthew, a category 4 hurricane on a scale of 5, is headed towards Haiti, where it is expected to have a catastrophic impact both tonight and tomorrow. Hurricane warnings have also been issued in Cuba and the Bahamas, and the storm is expected to move towards Florida later this week unless it changes course. The storm also is likely to have a negative effect on beach and boating conditions across the East Coast this week.
For perspective, here’s a satellite image captured by the National Oceanic and Atmospheric Administration (NOAA) of the storm passing over the south-central Caribbean Sea early Sunday morning:
It’s hard to know exactly how much this hurricane will impact the coastal regions it is currently heading towards, partly because the severity of key factors like storm surge is difficult to predict. Storm surge is described by NOAA’s National Hurricane Center as the abnormal rise of water that washes up on shore during a hurricane. It’s caused by the intense force of winds that move around the storm. The severity of storm surge depends largely on the size and intensity of the storm, and can also be affected by the depth of the continental shelf – a shallower shelf surrounding a coastal region is likely to produce a greater surge than a steep shelf.
2005’s Hurricane Katrina is perhaps one of the most devastating examples of this – the hurricane produced a surge of 25-30 feet above normal tide levels, devastating the coastal regions of Louisiana. Storm surge can have lasting effects on beaches in particular. For example, hurricanes can cause beach erosion, which occurs when strong waves and currents remove sand from beaches and carry it offshore. This causes shoreline retreat that can’t be remedied until calmer waves bring the sand back, which has a negative effect on both beach-related tourism – a significant part of why vacationers flock to places like Florida and the Bahamas – and local infrastructure.
Hurricanes are a naturally occurring event, so humans have little control over what they are going to do. However, scientists have been working for years to attempt to understand how hurricanes happen and to better predict the extent of effects like storm surge. For example, this 1998 article from CNN describes scientists who used laser beams to survey the coastline, with the hope of predicting which parts of the U.S. are most sensitive to coastal erosion.
Twenty years later, scientists use the SLOSH model (stands for Sea, Lake and Overland Surges from Hurricanes) to predict the height of storm surge. The model was developed by the National Weather Service and considers atmospheric pressure and forward speed to model the wind system that causes the surge.
Some scientists are heading straight into the eye of the storm to understand what causes hurricane formation. A group of collaborators from Woods Hole Oceanographic Institution (WHOI), Rutgers University, and others deployed a fleet of free-swimming underwater gliders earlier this month in the waters south of Martha’s Vineyard. The gliders lurked in the path of Hurricane Hermine, which had major effects in Florida and throughout the Caribbean as well as effects along the East Coast. The data will hopefully help scientists better understand how ocean conditions change as the storm moves along.
“One of the reasons it’s so hard to forecast is that intensity depends on sea-surface conditions directly ahead of and below the storm,” said WHOI physical oceanographer Glen Gawarkiewicz in a news release. “Gliders and other new instruments we are testing enable us, for the first time ever, to make measurements in these very harsh conditions.”
Despite exciting progress in hurricane research, when it comes to an impending storm like Hurricane Matthew, the main thing people can do is cross their fingers, close their doors, and wait to see what happens next.