San Diego

More Overnight Snow Expected on San Diego's Mountains

Even elevations as low as 2,000 feet could get a dusting of snow overnight, as temperatures drop across the county

More than a foot of potentially dangerous snow topped some of San Diego's mountains Thursday, prompting schools to cancel classes and highway officials to issue warnings on roads.

A National Weather Service winter storm warning remains in effect until 1 a.m. Friday due to the hazardous roadway conditions. A freeze warning was also issued for San Diego County valleys, including Escondido, San Marcos, Santee and Poway, and the Inland Empire from 10 p.m. Thursday to 9 a.m. Friday.

During the warnings, weather conditions will make travel very hazardous or impossible in the mountains, the NWS said.

By around 5 p.m. Thursday, Mount Laguna, with an elevation of 5,900 feet, had recorded 12 inches of snowfall, according to the National Weather Service. Lower elevations also saw significant snowfall:

Palomar Mountain: 12 inches
Julian: 9 inches
Boulevard: 1.5 inches
Pine Valley: 4 inch
Descanso: .5 inches

Snow was reported at elevations as low as 2,800 feet Thursday evening, though little was sticking to the ground. NBC 7 Meteorologist Dagmar Midcap said snowfall elevation would drop to around 2,000 feet overnight Thursday.

Caltrans closed State Route 79 between I-8 and the SR-79/SR-78 junction in Julian Thursday night due to snowy roadways. The gates were closed along SR-79 at Sunrise Highway. "ROAD CLOSED" signs had been placed in front of the gates.

Caltrans said just before 10 p.m. that I-8 was closed between SR-79/Japatul Valley Road and E. Willows Road due to snow and ice.

Firefighters responded to several spinouts and crashes on mountain roadways though, fortunately, none were injury crashes, Cal Fire spokesperson Issac Sanchez said. 

Sanchez urged drivers to avoid coming to the mountains for a few days and if drivers must travel in the area, to be prepared.

"It just isn’t really where you want to be right now," Sanchez said. "The best thing to do is avoid the area for the next day or two and then once things thaw out come on up and see what’s happening." 

Several mountain school districts canceled classes Thursday because of the inclement weather. The districts include: 

  • Julian Union High School District
  • Julian Union School District
  • Mountain Empire Unified School District
  • Spencer Valley School District
  • Warner Springs School District
Those districts would remain closed Friday, too, the San Diego County Office of Education confirmed Thursday afternoon.

The severe weather was also affecting San Diego's coast. SeaWorld San Diego said the park would be closed Thursday due to rain and winds along the coast. 

While San Diegans in several coastal and inland neighborhoods reported seeing hail, Midcap said it could have been one of the several types of frozen precipitation not considered hail.

To be considered hail, frozen particles falling from the sky must have a diameter thicker than 5 millimeters or a fifth of an inch, Midcap said.

Graupel, also known as snow pellets, are soft, small pieces of ice created when supercooled water droplets coat a snowflake.

Midcap says this distinction is important because for hail to form, the presence of a strong updraft, like what is found within a thunderstorm, is required to repeatedly lift the frozen precipitation up into the cloud where it freezes, then falls, partly melts, and gets lifted up again to re-freeze. The process repeats over and over each time forming a new layer of ice. That’s why if you were to cut open hail you would see layers of frozen water. Those layers make hail very hard which is why it can create a lot of damage.

Graupel, by comparison, does not have layers and is rather mushy, Midcap said. If you can pick it up and crush it between your fingertips, it’s very likely just graupel.

So, now you know!

An approximately 75-foot tall tree set in soaked soil was pushed over Thursday night and blocked the entrance to a Girls and Boy Scouts club near the intersection of Upas Street and Vermont Street in Hillcrest. No one was injured. 

So far, the 48-hour total rainfall forecast tabbed inland and coastal areas between .10 and .33 inches with another quarter- to half-inch of rain expected on Thursday. 

This bout of rain, however, won't be as heavy as last week's storms which were the products of an atmospheric river, Midcap said. 

Meteorologist Sheena Parveen said that by Friday, conditions were expected to be dry but chilly again.

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