The wind-whipped firestorm that tore through parts of Boulder County, Colorado, on Thursday struck at the heart of one of America's top climate science and meteorology research hubs.
The Boulder, Colorado-area wildfires — the most destructive in state history — were likely made worse by the effects of climate change, including extremely dry conditions and long stretches of record warm weather in recent months.
Why it matters: The Marshall Fire that consumed at least 1,600 acres on Thursday destroyed nearly 600 homes, Boulder County Sheriff Joe Pelle said at a Thursday news conference.
Ferocious hurricane-force winds helped spark wildfires that spread to over 1,600 acres and prompted hasty evacuations near Denver, Colorado, including the entire town of Superior and city of Louisville.
The latest: Colorado Gov. Jared Polis declared a state of emergency Thursday afternoon as a result of the fires, enabling the government to access emergency disaster funds in response to the situation.
A weather station mounted on a tide gauge on the picturesque island of Kodiak, Alaska, recorded an air temperature of 67°F on Dec. 26, which if verified would become the state's record high for the month.
The big picture: Such astonishingly mild conditions in America's Arctic state come at the end of a month that largely featured extreme cold across much of the region. The warm spell, which reached inland areas, turned snow into freezing rain that made roads sheets of ice early this week.
Why it matters: This freak temperature reading in a state known for its cold, snow and winter darkness puts a capstone on a year filled with extreme weather events in the U.S. and worldwide, many of which were made worse by global warming.
The weather station at the Kodiak tide gauge reached the 60s again Monday afternoon, and up to 55°F on Tuesday morning. "In late December," tweeted Alaska climate scientist Rick Thoman, "I would not have thought such a thing possible."
How it works: The warmth is due to a major, albeit relatively short-lived, shift in the jet stream, which is a river of air flowing at high altitudes that helps steer weather systems.
Instead of dipping south of Alaska and carving out a frigid trough of low pressure, as was the case during parts of November and much of December, the jet stream buckled in such a way that allowed mild, maritime air to surge in from the south.
What's next: Computer models indicate that once the heart of the frigid air seeps into the U.S., another batch is likely to reload across Alaska and make its way southeastward as well.
California's ski resorts are digging out from under 5 to 9 feet of snow that has fallen over the last several days from a series of storms. And more snow is on the way.
The big picture: A large dip, or trough, in the jet stream across the West is allowing frigid conditions and a relentless series of storms to bring record-breaking snowfall into the Sierra Nevada Mountains. The snow has closed major interstates and even forced the shut down of several ski resorts.
Threat level: The National Weather Service said significant snowfall hit West Coast mountain ranges and the Intermountain West, with record cold weather in the Pacific Northwest. Meanwhile, the U.S. South was experiencing "unusually warm temperatures," with dozens of cities in the lower 48 states on track for their warmest December on record.
Heavy rains and flooding in northeastern Brazil have killed at least 18 people, wounded 286 others and displaced some 35,000 residents, AFP reported Sunday.
The big picture: The Brazilian state of Bahia has been pummeled by heavy rains since early November, causing two dams to burst over the weekend as more deaths from the extreme weather were confirmed, Reuters notes.
Threat level: The storm that's equivalent to a Category 5 hurricane is the strongest typhoon to make landfall in the Philippines this year — causing over 300,000 people to evacuate coastal areas as it triggered flooding, communications and power outages and uprooted trees Thursday, AFP notes.
The body of a 13-year-old girl was found in a Kentucky neighborhood razed in last weekend's tornadoes and storms that lashed six U.S. states, raising the death toll in the state to 76 and 90 overall, per AP.
The big picture: Nyssa Brown was one of seven family members to die in the Bowling Green tornado. The National Weather Service has released preliminary findings showing that western Kentucky was hit by an EF-4 tornado on the Enhanced Fujita Scale — meaning the damage it caused was "devastating."
A massive, multi-hazard storm unprecedented for mid-December in the Plains and Upper Midwest affected nearly 100 million people from New Mexico to Wisconsin on Wednesday into Wednesday night.
Why it matters: The latest storm is yet another demonstration that the dial on the extreme weather meter has gone all the way to 11 during 2021. Many of the events this year, including this one, bear the hallmarks of climate change.