One person was killed and several were rescued after torrential rain from an atmospheric river caused severe flooding in Redding, northern California, on December 21–22, 2025. Rainfall totals above 100 mm (4 inches) overwhelmed storm drains, flooded roads.
A tornado touched down in a rural area near Santa Rosa del Monday, Alto Paraná Department, on December 21, 2025, amid severe thunderstorms affecting eastern Paraguay. The phenomenon was documented on video by residents, with reports of localized damage to vegetation and infrastructure but no confirmed casualties.
Three atmospheric rivers are expected to impact California between December 20 and 25, 2025, producing 250–500 mm (10–20 inches) of rain over the Sierra Nevada and 75–180 mm (3–7 inches) over southern coastal ranges. The strongest system is forecast to peak on December 23–25 with IVT values surpassing 750 kg m⁻¹ s⁻¹ and AR3–AR4 intensity.
A dam in Ponte Alta do Bom Jesus, southeast of Tocantins, Brazil, suffered a partial failure on the morning of December 19, 2025.
Forecast models indicate that the Polar Vortex will strengthen in late December 2025 after a split and disrupted phase earlier in the season. The recovery is expected to influence North American and European weather in January 2026, potentially sending colder air southward while reorganizing jet stream flow.
A series of impactful atmospheric rivers is forecast to bring heavy precipitation across California from Friday, December 19, 2025, through Wednesday, December 24, with seven-day precipitation totals expected to exceed 380 mm (15 inches) in parts of the Sierra Nevada.
The National Weather Service (NWS) office in Boulder issued a Particularly Dangerous Situation (PDC) for rapid wildfire spread affecting the foothills and along Colorado Highway 93 through Friday, December 19, 2025.
A powerful windstorm with gusts reaching 232 km/h (144 mph) battered parts of the Pacific Northwest and Rockies this week, leaving one dead, two injured, and hundreds of thousands without power by December 18, 2025. The deep low-pressure system continues moving east toward the northern Plains and Midwest, sustaining severe winds and wildfire risks.
New activity/unrest was reported for 5 volcanoes from December 10 to 16, 2025. During the same period, ongoing activity was reported for 17 volcanoes.
A strong M7.0 oblique-slip earthquake struck beneath the Hubbard Glacier in the St. Elias Mountains, about 89 km (55 miles) north of Yakutat, Alaska, at 11:40 AKST (20:40 UTC) on December 6, 2025. The quake triggered widespread ground failures, with over 700 landslides and snow avalanches identified across Alaska and Canada. The largest and most concentrated slope failures occurred within a 16 km (10 miles) wide band along the estimated fault rupture.
