By Miriam Raftery
Photo: Stock image of cloud-to-cloud lighting (not today’s jolt)
January 31, 2019 (La Mesa) – A lightning bolt between Lemon Grove and La Mesa this afternoon produced a prolonged thunderclap loud enough to be heard as far away as Fletcher Hills, Lake Murray, Mission Gorge and Rancho San Diego. The noise startled residents and terrified pets, but fortunately the bolt did not result in any reported damage.
At my Mt. Helix home, the whole house shook as rumbling continued for approximately 30 seconds after the initial roaring jolt.
According to Alex Tardy, a forecaster with the National Weather Service in San Diego, the power of a lightning bolt and ensuing thunder is determined both by the amount of voltage and the length of the bolt. Voltage may be positive or negative, with positive voltage the most powerful. By late afternoon, 21 positive strikes were recorded in San Diego County west of the mountain areas. The NWS confirms only the one lightning bolt in East County between 2 and 2:30 p.m., ruling out the possibility that people heard thunder from separate lighting strikes.
Tardy says the bolt heard across much of East County was likely a positive voltage in a cloud to cloud flash that produced the intense shaking. No cloud-to-ground lightning bolts were detected by the NWS. “It’s shocking a long area, so you are hearing that sound, which is delayed, just linger on and on.” He says of intense cloud-to-cloud bolts. Positive strikes are relatively unusual in our region, the meteorologist explained.
On the Mt. Helix Next Door forum, many residents posted their reactions.
An employee in La Mesa wrote, “At work on Allison, the thunder was an extended uninterrupted roll, shook the windows, and set off multiple car alarms outside. Never heard anything like it in CA for sure…”
A Northmont Ave., La Mesa resident posted, “Holy Smokes!!! I thought my house was going to crumble down around me! Sheesh!!!”
“It was the most impressive thunder clap I’ve ever heard!” a resident on Lemon Ave. in La Mesa observed.
A Mt. Helix resident stated, “Our old house shook, too. Crazy.”
Dianne Walker of Fletcher Hills wrote, “Cat on my lap went flying. No blood, thank goodness.”
In El Cajon, a resident who heard the loud thunder wrote, “When we got home our boxer somehow leaped over our 6 foot fence and was hiding under my husband’s truck. Poor girl was terrified!”
A former New Mexico resident who was in the Dollar Store at Grossmont Center in La Mesa says “the large window panes rattled but thank goodness no cracks or breakage. That was INTENSE! I don’t recall anything like that in Albuquerque. The get some severe lightning and thunder there.”
A Joel Lane resident said, “I am from Iowa and have experienced loud thunder and lightning but for here that was a big one!”
Another poster from El Cajon says, “It was almost like an earthquake in the way it shook the house!”
A motorist pumping gas on Spring Street in La Mesa said the ground shook and he heard what sounded like “four loud cannons”
Ellen Yim of El Cajon said, “Scared the living daylights out of my one cat.”
Rae Belliard in the Mariposa Park neighborhood of La Mesa women says she came home shortly after the jolt to find her small dog had jumped out of a locked indoor pen and was snoozing on her bed. “I’m sure the lightning bolt provided enough impetus for her to take the leap!” she deduced.
The storm also dumped up to an inch and a half of rain in some parts of the county, with the heaviest downpours in North County.
The storm caused the city of La Mesa to shut down Palm Avenue at Lemon until tomorrow, also causing minor flooding in low points in Sprint Valley and other flood-prone spots across the region.