2 tornadoes in NJ this week: Destroyed deck among damaged homes

Next time a weather alert warns you about a tornado in your county, take cover!

A National Weather Service storm survey team confirmed that storms in South Jersey on Thursday night resulted in two tornadoes touching down and causing serious damage, including destroying a backyard deck, which was caught on video. There were no reported injuries.

Tornado Warnings were issued as the storms developed after 7:30 p.m. with dark clouds, heavy rain and high winds.

This determination was made by a "storm survey," according to New Jersey 101.5 Chief Meteorologist Dan Zarrow. He said officials from the National Weather Service went into the field and looked at the storm damage to determine the cause (straight-line winds vs. a tornado), the track and the approximate strength.

"It's a fascinating process that involves a lot of engineering and meteorological knowledge and research," Zarrow said.

The survey team's conclusions:

One storm in the Mullica Hill section of Harrison Township was an EF-0 tornado on the Enhanced Fujita Scale with an estimated maximum wind speed of 60-70 mph that developed around 8:15 p.m. near the Saddle Court development. Fencing at one home was damaged, a gutter was ripped off another and backyard furniture was lifted about 50 yards. It also caused a narrow path of tree damage.

A second storm about 8:30 p.m. in Deptford and the Blackwood section of Gloucester Township was determined to be an EF-1 with an estimated maximum wind speed of 90-100 mph. It traveled 1.3 miles in a "non-continuous path" that damaged three homes in Deptford with fallen trees. An uprooted tree also damaged an apartment building.

A third windy weather event in Salem County with wind speeds of 60-80 mph was determined to be caused by straight-line winds.

"The 'two tornado' declaration is a bit misleading because they both came from the same storm," Zarrow said. "Tornado #1 touched down briefly near Mullica Hill. Then the funnel lifted for a few minutes. As rotation tightened up again, the same storm spawned Tornado #2 near Deptford. This one was stronger, bigger, and longer-lived."

On average, New Jersey sees two to three tornadoes a year, according to Zarrow, So far this year, we're up to three confirmed tornadoes. That's in addition to two suspected tornadoes in Cumberland and Warren counties on May 28 that never had a storm survey.

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Zarrow doesn't have a definitive answer as to why spring has been so active.

"Tornadic storms require a very specific set of conditions to form — not too hot and not too cool, with just enough moisture, instability, and wind shear in the atmosphere. And we've just had that setup several times over the past month," he said. "We'll all have to be extra-vigilant for more damaging and/or life-threatening weather.

Contact reporter Dan Alexander at Dan.Alexander@townsquaremedia.com or via Twitter @DanAlexanderNJ