First tornado to touch down in Nassau County in 5 years: How rare are tornadoes on Long Island?
A dramatic waterspout formed off the south shore of Long Island Thursday evening, then moved toward shore and caused extensive damage at two beach clubs in Atlantic Beach.
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It's been nearly five years since the last confirmed tornado touched down in Nassau County, but the National Weather Service has confirmed that Thursday evening's waterspout that caused extensive damage at two beach clubs in Atlantic Beach between 6:30 p.m. and 7 p.m. was a tornado. It's too early to confirm the strength of a tornado. It's the first tornadic waterspout in Nassau County in years, but tornadoes are not as rare as you might think.
THE TWO TYPES OF WATERSPOUTS
Not all waterspouts come from violent thunderstorms. A waterspout is a rotating column of air associated with a visible condensation funnel over water.
A fair-weather waterspout is generally a relatively weak phenomenon that develops beneath growing cumulus clouds when the water is warmer than the air above it. This typically happens under very calm conditions which causes tiny pockets of warm air to rapidly rise called "thermals". These can spin with winds typically 40-60 mph.
Fair weather waterspouts move very slowly and rarely make it onto land. If they do, they dissipate quickly, but can cause damage.
A tornadic waterspout is produced by a violent rotating supercell thunderstorm just like the tornadoes we're familiar with on land. The strength of a tornado can only be measured by the damage it produces so these tornadic waterspouts will go undocumented unless they're visually seen or make it onto land.
That is an important point because the visual appearance of a waterspout can be misleading. A large, dramatic funnel does not automatically mean extreme winds, just as a relatively narrow visible funnel does not mean the circulation is harmless.
HOW STRONG WAS THE NASSAU COUNTY TORNADO?
Unlike hurricanes, the strength of a tornado cannot be determined until after the damage is surveyed by the National Weather Service. The National Weather Service will have the final say when they survey the damage this morning, but there is evidence that this was a tornadic circulation. Multiple videos show a clear funnel that touched down and produced damage at the Sun and Surf Beach Club and nearby Silver Point Beach Club. The tornado only lasted a few moments before it lifted.
The tornado's Enhanced Fujita, or EF, rating will be based primarily on the damage it caused.
ENHANCED FUJITA SCALE | WIND SPEED |
|---|---|
EF - 0 | 65 - 85 MPH |
EF - 1 | 86 - 110 MPH |
EF - 2 | 111 - 135 MPH |
EF - 3 | 136 - 165 MPH |
EF - 4 | 166- 200 MPH |
EF - 5 | 200+ MPH |
The National Weather Service determines tornado intensity using damage indicators. Investigators examine how structures failed, the quality of construction, trees, utility poles and other objects affected by the circulation. They then use the observed degree of damage to estimate the wind speed associated with that damage.
HOW RARE ARE TORNADOES ON LONG ISLAND?
Tornadoes are uncommon on Long Island, especially Nassau county which has only reported 2 tornadoes in the past 20 years. Since 1950, a total of 9 tornadoes have been reported in Nassau county and 32 tornadoes have been reported in Suffolk county.
Typically most tornadoes on Long Island fall under an EF-0 or EF-1 rating. The most recent confirmed tornado on the island was nearly 4 years ago in September 22, an EF-0 near Mattituck with winds estimated between 75-85 mph.
The biggest single day tornado outbreak on the island was nearly 5 years ago on November 13, 2021. This was remarkably the first time tornadoes have ever been reported after October. Nassau county reported an EF-0 that touched down in a few spots between Woodmere and Levittown. Suffolk County reported 5 tornadoes that day.
THE STRONGEST TORNADOES
The strongest tornado to hit the island was an F2 which happened most recently in Mattituck on Aug 8, 1999. The tornado touched down and lifted several times along a roughly 4-mile path across the North Fork, causing widespread damage to trees, homes, roofs and porches. The most severe damage occurred near Jackson Avenue and Fifth Street, where winds were estimated at 110–120 mph and damage was rated F2. The tornado produced winds over 100 mph in other areas, with numerous mature trees snapped or uprooted and homes damaged by falling trees and debris. Total damage was estimated at more than $1 million, and one person was injured by flying debris.
The most costly tornadoes have typically produced 1 million dollars worth of damage on the island. While several of these tornadoes have caused injuries, there have been no confirmed fatalities directly related to a tornado on Long Island over the past 56 years.
