Thunderstorms

BEND, Ore. –

Strong thunderstorms rumbled northward through the High Desert Sunday afternoon and evening, kicking up winds, dropping large hailstones from darkened skies and sending sizzling temperatures plunging up to 24 degrees. Hwy. 20 drivers near Santiam Pass encountered golf ball-sized hail, heavy rain and flooding from a storm of “biblical proportions.”

A National Weather Service spotter northeast of La Pine reported one-inch hail around 4 p.m. and said the 90-degree temperature had dropped to 66 degrees. An area resident reported hail and heavy rain lasting close to an hour.

The NWS issued “significant weather advisories” several times in the late afternoon and evening as Doppler radar tracked strong thunderstorms moving north through the region, from La Pine and Bend to areas east of Prineville. They warned of hail to the size of nickels or pennies, and winds gusting to 40-50 mph, along with heavy rain in places.

Then, around 5:15 p.m., a severe thunderstorm warning was issued for northwest Deschutes and western Jefferson counties until 6:15 p.m., due to a storm near Black Butte Ranch, moving north at 15 mph. Forecasters said that one could produce quarter-sized hail and damaging winds topping 60 mph, as well as heavy rain. Camp Sherman was in the warning area.

Judey Berray of the Black Butte Ranch Welcome Center told NewsChannel 21 Sunday evening that arriving guests were reporting “an incredible hailstorm” coming down from Santiam Pass on Highway 20.

“The hail was golf ball-sized, cars were pulling over to get under trees until it passed, (and it was) raining so hard it was flooding down the road, making for very treacherous driving,” Berray wrote. “(The occupants of) car after car told us it was unreal; like nothing they’d ever seen before, and even commented the hailstorm was of biblical proportion.”

As that thunderstorm moved on, a new severe thunderstorm warning was issued until 7 p.m. for northwest Crook and eastern Jefferson counties as a severe thunderstorm 11 miles northeast of Prineville was moving northwest at 20 mph, capable of producing nickel-sized hail, winds topping 60 mph and even some “weak rotation” that could produce a tornado, though it was deemed “not immediately likely.”

NewsChannel 21 Meteorologist Travis Knudsen said the dry conditions and lightning threat pose a risk of wildfires throughout the region.

Just as Central Oregon starts getting its first real string of hot summer weather, the NWS issued a “red flag warning” for thunderstorms, abundant lightning and rising wildfire danger across the High Desert and other areas to the south and east.

The NWS in Pendleton put the warning in effect from noon Sunday to 10 a.m. Tuesday, from the east slopes of the Central Oregon Cascades to the Deschutes National Forest and the state’s central mountains, as well as the southern Blue and Strawberry mountains.

“A southerly flow will bring hotter temperatures and increasing moisture to the forecast area, resulting in an increasing period of thunderstorm activity,” forecasters warned.

The storms will taper off Sunday night, but a new round is predicted to develop Monday and Monday evening. Fortunately, some slow-moving storms are expected to contain significant moisture, dropping rain that could reduce the fire risk in the forests.

Still, the lightning and dry fuels could result in numerous fire starts, fanned by gusty and erratic winds with some thunderstorms.

A red flag warning means critical fire weather conditions are expected, with a combination of strong winds, low humidity and warm temperatures to “create explosive fire growth potential.”