Charleston, South Carolina, is highly susceptible to hurricanes and tropical storms due to its coastal position in the southeastern United States. The city sits on a peninsula, directly exposed to the Atlantic Ocean and the frequent paths of tropical systems. Residents and visitors must remain aware of the city’s significant historical exposure to powerful storms. Preparation for hurricane season is a serious consideration for everyone in the Lowcountry region.
Historical Impact and Frequency
Charleston has a long history with tropical cyclones, experiencing impacts from over 30 significant storms since 1670, which averages to a memorable storm every ten years. The most active time for the strongest storms in the region is typically from late August through early October. Since 1851, the South Carolina coast has seen 45 tropical cyclones make landfall, with four arriving as major hurricanes of Category 3 or higher.
The most devastating modern event was Hurricane Hugo in September 1989, which made landfall just north of Charleston as a Category 4 storm. Hugo produced tremendous wind damage and a massive storm surge that reached up to 20 feet in Bulls Bay. While the Charleston peninsula was spared the worst of the surge, most buildings in the historic downtown area sustained significant damage, and nearly 80 percent of roofs were affected.
More recently, Hurricane Matthew in 2016 and Hurricane Irma in 2017 caused extensive storm surge flooding in downtown Charleston. Matthew produced a storm surge of approximately 6.2 feet in Charleston Harbor. These events confirm that tropical storm-force winds and storm surge remain a constant danger, regardless of a system’s precise category or landfall location.
Geographical Factors Increasing Vulnerability
Charleston’s geography is a primary reason the city is so vulnerable to the destructive power of tropical systems. The historic downtown peninsula is exceptionally low-lying, making it highly susceptible to storm surge and tidal flooding. Most of the peninsula’s residents already live within the Federal Emergency Management Agency’s 100-year flood zone. This low elevation means even a modest storm surge, or surge combined with high tide, can lead to catastrophic coastal inundation.
The city’s position at the confluence of the Ashley and Cooper Rivers, which form the Charleston Harbor, creates a funneling effect. This geographical choke point tends to amplify the height of incoming storm surge, pushing water into the low-lying downtown area and surrounding communities. Barrier islands like Folly Beach, Sullivan’s Island, and Isle of Palms offer limited protection and are themselves exposed to erosion and direct wave action. Coastal flooding is the most significant threat to the downtown area, with flood depths approaching two meters in the most extreme events.
Current Season Outlook and Local Alerts
The Atlantic Hurricane Season officially runs from June 1st through November 30th each year. Peak activity occurs in August, September, and early October. Residents and visitors need to actively monitor official sources for information during this six-month period. Official, local alerts and emergency instructions are disseminated by the Charleston County Emergency Management Department (CCEMD).
The National Weather Service uses specific terms to communicate the level of threat. A Hurricane Watch is issued when hurricane conditions (sustained winds of 74 mph or higher) are a possibility within 48 hours. Preparatory actions should be taken immediately. A Hurricane Warning is a more urgent message, issued when hurricane conditions are expected within 36 hours, and precautionary actions, including any necessary evacuation, should begin. The CCEMD also utilizes a Citizens Alert Notification System to provide time-sensitive messages to registered users via phone, text, and email.
Preparation and Safety Specific to Charleston
Effective preparation requires knowing the specific hazards and official directives for the Charleston area. The most important step is identifying your specific hurricane evacuation zone, designated by letters such as Zone A, B, or C, based on local storm surge models. These zones are used by state and local authorities to issue mandatory evacuation orders. Evacuation should only be attempted when ordered, and evacuees should become familiar with their designated routes.
The primary evacuation route is Interstate 26 heading west towards Columbia. In the event of a mandatory evacuation, the state can implement a lane reversal on I-26, where all lanes flow one-way away from the coast. For those in the West Ashley area, the route often involves taking SC 61 to US 78, while downtown evacuees use the normal westbound lanes of I-26.
Local hazards extend beyond wind and surge, including the high risk of power outages that can affect historic homes and tidal flooding, which can inundate streets even before a storm arrives. Residents should assemble an emergency supplies kit with provisions for at least 72 hours, as emergency services may be delayed after a major event. Securing property means anchoring loose outdoor items and preparing for the immediate, localized flooding common in low-lying neighborhoods.