Massive Winter Storm Slams the Southern, Eastern USA

Written by Team Morecast

 

A powerful upper level low spinning out of northern Mexico met a surge of Arctic air to produce dangerous wintry precipitation from the Southern Plains through the Midwest to the Eastern Seaboard. Crippling ice, heavy snow, and even severe storms have occurred with this system. More than a million residences were without power at one time or another. Some of these power outages will linger for several days, a very dangerous scenario with temperatures well below freezing in the forecast. At least 11 deaths are blamed on the storm as of Sunday night.

 

 

 

The northern side of the system featured heavy snow with accumulations of 8-16 inches (20-40 cm) in the mid-Plains and Midwest. As much of 20 inches (50 cm) has fallen in the interior Northeast and southern New England. A zone to the south saw sleet accumulations of 2-5 inches (50-125 mm) and icing over an inch in some spots. The hardest hit area for icing has been from eastern Texas through northern Louisiana and Mississippi to west-central Tennessee. Hours of thundersleet and heavy freezing rain have taken out many if not most branches in some communities, leading to widespread power outages. Power crews working in this area were forced to suspend restoration efforts because large trees branches were breaking off and hitting workers in their bucket lifts. More than 17,000 flights have been cancelled, including all flights in or out of Reagan National in Washington, DC. Sunday was the worst day for flight cancellations since the early part of the pandemic in 2020.

 

 

Severe storms were confined to the area near the Gulf Coast in southern Mississippi and Alabama as well as the Florida panhandle. But damaging winds exceeding 70 mph (113 kph) and even a few tornadoes were reported in this region.

Wettest Christmas in Decades Brings Flooding, Mudslides to California

Written by Team Morecast

 

The so-called Pineapple Express, a persistent train of rich tropical moisture, brought days of heavy rainfall to California. The L.A. Basin was hardest hit on Christmas Eve and Christmas Day. Numerous daily rainfall records were broken with two-day totals from three to six inches (150 mm), equivalent to several months worth of normal rainfall. The copious rainfall has resulted in significant flooding along with life-threatening debris slides. A state of emergency has been declared in six counties.

 

 

 

Northern California was hit first early in the week. Serious flooding impacted Redding (see above). The atmospheric river then shift south to Southern California in the last few days. Buildings and cars were buried by mud and rocks in Wrightwood, California (see above). Many residents were forced to evacuate, and a few even had to be rescued by helicopter from their rooftops. A section of Interstate 5 was closed due to high water and stranded vehicles on Thursday in Sun Valley (see below), not far from the Burbank Airport. Burn scars from the massive wildfires on the west side of Los Angeles are particularly dangerous due to increased debris and poor capacity to absorb runoff. This risk has prompted evacuations there.

 

 

 

The heavy precipitation is falling as blinding snow in the southern Sierra Nevadas. Storm total accumulations could approach eight feet. Elsewhere, wind gusts as high as 80-100 mph (130-160 kph) have raked exposed coastal and high elevation sites. The combination of high winds and rain-loosened soils increase the risk of downed trees and powerlines and the resultant prolonged power outages.

Record-Shattering Floods Trigger Mass Evacuations in the Pacific Northwest

Written by Team Morecast

 

Days of torrential rainfall in the Pacific Northwest have pushed rivers to major if not record-breaking levels. This catastrophic flooding has inundated towns across much of western Washington state, forcing upwards of 100,000 residents to evacuate. A state of emergency has been declared with officials urging everyone within the 100-year flood plain to seek higher ground immediately.

 

 

 

 

It’s been a wet pattern for several weeks in the region, but the heavy rains began in earnest on Sunday. The past several days have been a steady deluge of 1-3 inches (25-75 mm) per day with some localized amounts to 4 inches (100 mm). Overall totals have probably exceeded a foot in the west-facing slopes of the Cascades. The tremendous runoff has pushed most rivers to major flood stage. The Skagit River will crest today potentially several feet above the previous record, leading to near total inundation in an important agricultural valley. Major road closures and numerous water rescues have been necessary. Landslides are also a serious concern in the steeper terrain with I-90 partially closed by one east of Seattle late Wednesday. Amtrak rail service has been shut down indefinitely. Major arteries have also been closed in southwest British Columbia, Canada, effectively isolating the city of Vancouver.

Two Days of Monster Supercells Leave Trails of Destruction Around Brisbane

Written by Team Morecast

 

An extremely unstable weather pattern has taken hold over southeastern Queensland, Australia this week. Intense supercell storms roared across the region around Brisbane each of the past two days. The supercells have brought giant hail and destructive winds to many communities, smashing cars and house roofs. In some cases the same towns have seen damaging hail on both days.

 

 

Sunday’s round of severe storms included a long-lived supercell that travelled over 60 km from near the border of Queensland and New South Wales all the way up to the eastern suburbs of Brisbane. Hail stones of 7-9 cm (2.75 to 3.5 in) fell along this path, peaking just southeast of Brisbane in the towns of Eagleby and Loganholme. Other isolated supercells dropped baseball-size hail in Silver Spur to the west and Glen Innes in northeast NSW.

 

 

A larger cluster of supercells developed on Monday near the Gold Coast and raced up the coast through Brisbane and Hervey Bay. Even more destructive hail was generated with these storms with many reports of stones exceeding 10 cm (4 in) in diameter. The largest stones struck Chandler, just east of Brisbane, measured at 13-14 cm (5-5.5 in) in diameter, not much shy of the national record of 16 cm. Needless to say, the damage to roofs and car windows has been catastrophic, especially in towns like Loganholme that have been struck twice. As the storms moved north, the threat transitioned to high winds. Possible tornadoes struck Wallu and Bribie Island with wind gusts at least 150-180 kph (90-110 mph) flipping cars and knocking down trees and powerlines.