Currently in Boston — January 10th, 2023

The weather, currently.

Seasonable and dry weather until later Thursday.

Clear skies overnight will allow temperatures to fall back down to the upper twenties. Temperatures will be in the upper thirties tomorrow with sunshine and only a few clouds, which is very typical for this time of year. On Wednesday, after a cold start, readings will get back to the mid-30s along with a blend of clouds and sun. As precipitation arrives Thursday with some cold air, there could be a little bit of snow before it change to rain, but no accumulation is expected. Friday looks wet and mild with readings in the 50s. This will all come to an end Saturday, followed by cooler weather and sunshine for Sunday, into Martin Luther King Day.

Dave Epstein

What you need to know, currently.

US President Joe Biden has declared an emergency in California due to the “bomb cyclone”, allowing federal aid to flow into the state.

The National Weather Service warned of a “relentless parade of atmospheric rivers,” as storms continue to make their way across the Pacific. Last week, the storms interrupted road travel with flash floods, rock slides, and fallen trees. This week, the storms continue to bring the risk of mudslides, high mountain snowfall and river flooding as well.

Gavin Newsom, the state’s governor, said 12 people have been killed by the violent weather in the last 10 days and more than 135,000 customers in California were left without power on Monday morning. The Office of Emergency Management issued evacuation warnings for multiple areas across Santa Barbara County “due to potential flooding and debris flows.”

Flash flood warnings are in effect for Santa Cruz and Monterey Counties. Locations along the San Lorenzo River in Felton are already at the major flood stage.

According to the California Highway Patrol, water rescues are taking place in the Santa Cruz area.

“Along the coast and low lying areas, many locations have seen at least 10 inches of rain in the past two weeks,” said Anthony Torres, Currently’s Head of Science. “The San Francisco International Airport (SFO) has actually measured 9.79 inches from Dec. 26 through Jan. 8. In some of the upsloping regions in the mountains, those totals exceed 20 inches. These and heavy mountain snows have impacted such a large area that the entire region is extremely waterlogged — and any additional rainfall only exacerbates the ongoing flooding situation.”

According to the SFO, “normal” precipitation from Dec. 26 through Jan. 9 is about 1.97 inches. We’ve seen about five times that over the past couple of weeks. The same applies for much of Northern California.

There are already several more atmospheric river storms across the Pacific, and they have the potential to be even more dangerous than those of last week.

“Unfortunately, another round of heavy rain is moving over these same areas as we speak,” Torres said. “The NWS’ flood watches are posted across the entire region with another 2-5 inches expected in the valleys, 4-7 inches in the hills, and 6-12 inches in the mountains.”

“The biggest issue with these storms are not so much each individual storm, but the broader weather pattern where multiple atmospheric rivers continue to soak the California coastline,” Torres continued.

Alongside the heavy rainfall are strong winds. Sacramento had several 60 to 70 mph ones that knocked out power and trees, blocking roads and other passageways, according to Torres.

California’s hydrological whiplash from long-term drought to extreme flooding, can be attributed to rapid arctic warming, which leads to more frequent and extreme periods of heavy rain, as well as drought, which we wouldn’t otherwise experience without this warming. A warmer atmosphere can also hold more water, making weather systems more wet than they otherwise would be.

In other words, human-induced climate change is playing a part in exacerbating the effects of these extremes.

—Aarohi Sheth

What you can do, currently.