Warm and dry conditions could bring “moderate heat risk” to parts of California’s Central Valley, where the National Weather Service (NWS) warned that temperatures could climb to the mid-90s. At the same time, floods are becoming faster and furious.  

While a modest breeze could develop by Wednesday evening along the coast, inland areas will continue to experience highs “around 10 degrees above average,” according to the NWS. 

“We do have an unusual weather pattern across the western U.S. and Western Canada right now,” University of California, Los Angeles climate scientist Daniel Swain said during virtual office hours earlier this week.  

He described the pattern as “extreme,” explaining that there has been a high-pressure ridge — an elongated zone accompanied by hot and dry weather — over Western Canada. 

This event shares some commonalities with the “unbelievably extreme heat wave” that occurred in June 2021, Swain said. But he also highlighted some key differences.  

Since the current event is happening in mid-May rather than in late June — and because the system’s center is farther north — temperatures are not quite as high across the entire region, Swain explained.   

But he recognized that some areas are enduring record-breaking highs, and that the hot conditions are up against an ongoing wildfire outbreak in Alberta and British Columbia.  

“It may get even worse in the coming days, with wind shifts and additional heat, along with the potential for some dry lightning up there,” Swain added.  

As this unseasonable heat wave continues, the NWS meteorologists urged residents to take necessary precautions.  

“People should practice heat safety by staying hydrated, dressing light, knowing where to find shade, and looking before locking their cars for elderly, pets and children,” the meteorologists advised.  

Both the NWS forecasters and Swain reminded residents that the increasingly warm temperatures are driving ongoing — and potentially treacherous — snowmelt, following an unusually wet winter.  

“Snowmelt is once again accelerating,” Swain said. “The big melt is not occurring in just one giant pulse but it’s just in these successively larger pulses.” 

In Central California’s San Joaquin Valley and the Tulare Lake Basin, he warned of prolonged floods, stressing that this is “going to be a story that continues to unfold.” 

“The peak is probably yet to come. It’s just been slow in coming,” Swain said.  

Along these lines, the NWS meteorologists delivered an ominous message, noting that “waterways are still running cold and fast due to snowmelt.”  

“Beware of area waterways!” they stated.   

Welcome to The Hill’s Sustainability newsletter, we’re Saul Elbein and Sharon Udasin — every week we follow the latest moves in the growing battle over sustainability in the U.S. and around the world.

Exposure to air pollution overwhelms a key mechanism by which lung cells defend themselves, a new study has found. 

The findings, published on Tuesday in Autophagy Reports, may help explain the precise means by which air pollution causes lung disease. 

A hidden pathway: Scientists have long understood that tiny floating particles in the air — particularly those with a diameter smaller than 2.5 microns, known as PM 2.5 — are linked to a wide array of lung diseases. 

• These can include devastating and expensive illnesses like lung cancer and chronic obstructive pulmonary disease. 
  
  
• “What we don’t know are the mechanisms by which that occurs,” senior author Edward Crandall, a professor of pathology at University of Southern California, said in a statement. 

Why that matters: Air pollution leads to about 7 million early deaths per year, according to the World Health Organization. 

Eating-based defense: Crandall’s study looked at a main line cell protection called “autophagy” — literally “self-eating.” 

• Despite the dramatic name, autophagy is a normal form of cellular life: it’s the process by which cells digest and recycle components that are diseased, aged or simply unnecessary.  
  
  
• By treating lung cells with a special dye, researchers could track how much autophagy was happening in cells exposed to air full of dissolved particles. 

Maxed out: When exposed to the simulated air pollution, autophagy increased as cells sought to prune damaged tissues — but only up to a point. 

“The implication of these studies is that autophagy is a defense mechanism that has an upper limit, beyond which it can’t defend the cell any further,” Crandall said. 

Compound threat: But this systemic overload may have other potentially dangerous effects — such as compromising the ability of lung cells to ward off unrelated threats, according to the study. 

• For example, cells rely on autophagy to trim away parts damaged by other causes — like smoke inhalation or bacterial infection. 
  
  
• But just how deadly these additional threats are still needs to be tested, the scientists noted. 

Finding a cure: “The more we know about the mechanisms by which diseases occur, the more opportunity we have to find places in the pathway where we can intervene and prevent or treat the disease,” Crandall added.