Play Live Radio
Next Up:
0:00 0:00
Available On Air Stations

Cliff Mass Answers Listener Questions On The Blob, Full Moons And Ski Season Outlook

Tim Durkan

If you ever have a question about the weather, KPLU weather expert Cliff Mass wants to hear it. We’ve assembled answers to a range of listener queries and will be answering them over the next two weeks. Here’s the first batch.

Is There Less Cloud Cover On Full Moon Nights?

A listener who goes by the handle "Nightvision" wrote in with a nocturnal question, noting “it appears that on full moon nights, there’s less cloud cover. Is this true or am I dreaming?”

“I think they’re dreaming,” said Mass. “There’s no reason to think that the full moon — or a half moon or a new moon or any moon — has anything to do with the atmosphere."  

Why Does South Puget Sound Sees More Snow?

"Nabil" asks: "Why does the south Puget Sound almost  always seem to be the big winner when we get low-elevation snow in western Washington?”

“Well, that makes sense,” said Mass, “because the water is the enemy of snow.” If you’re near the water, which is relatively warm around here – maybe even 50 degrees in the middle of winter – that works against the formation of snow. People living on the coast or in the Strait of Juan de Fuca or Georgia, or even on the wider parts of Puget Sound tend to get less snow because of the proximity of a large body of water that’s many degrees above freezing.

“That really modifies the temperatures, making it less likely for snow,” Mass said. “And in South Puget Sound, they’re further back from the water, in places such as Olympia, Tacoma or Enumclaw and Black Diamond, the chance of snow increases substantially, because you’re miles away from that water. And Puget Sound is much narrower in the south Sound than it is further north.”

Will The Blob Affect Snowpack?

"Netcentric" asked: "What effect do you expect the continuing warmth in the north Pacific (surface temperatures) to have on snowpack, specifically water and drought in North America?”

The warm water off the coast is something Mass has blogged and talked about a lot this year is what he and some others have referred to as “the Blob.” He says it’s weakening a bit but is still there.

“But the blob is probably of secondary importance during the winter time,” Mass said. “During the summer, we have air going over this warm water and there isn’t much circulation, so having this pool of makes a big difference.”

But during the winter time, when winds are much stronger, they pull in air from much further away, and that reduces the warming effect. “So having this blob of a little bit warmer water offshore doesn’t have as big an impact," he said.

The bottom line, says Mass: The blob may warm us up slightly, but it’s not going to have much of an influence on how much snow we get during the wintertime.

What's The Ski Season Outlook?

Henry Lin asked via Facebook: "What is the seasonal forecast for the ski areas in the Cascades this winter?’

Mass says the main thing to know in considering this very popular question is that this winter has shaped up to be a weak El Niño. “Not a strong one, but a weak one,” said Mass/ “And the tendency for El Niños is to cause us to have less snow in the mountains." That's because El-Niño years bring warmer than normal temperatures and less precipitation.  

But since it is a weak influence this winter, the impact will be less than a really powerful one would be, Mass says, “but the dice are probably weighted to having less snowpack than normal this winter.”


The weekly KPLU feature "Weather with Cliff Mass" airs every Friday at 9 a.m. immediately following BirdNote, and twice on Friday afternoons during All Things Considered. The feature is hosted by KPLU Environment Reporter Bellamy Pailthorp. Cliff Mass is a University of Washington Professor of Atmospheric Sciences, a renowned Seattle weather prognosticator, and a popular weather blogger. You can also subscribe to a podcast of “Weather with Cliff Mass” shows.

Bellamy Pailthorp covers the environment for KNKX with an emphasis on climate justice, human health and food sovereignty. She enjoys reporting about how we will power our future while maintaining healthy cultures and livable cities. Story tips can be sent to