We certainly know that Krakatoa caused some major cold here. The winters of 1883-84 and 1884-85 both had top tier stuff here. Feb 1884 and Dec 1884 in specific. Both months were truly extraordinary for cold, duration of cold, and snowfall. It is a serious bummer we have no records for 1816-17 and 1817-18 for this region in the wake of the Tambora eruption. I'm not sure if there is any possible way to reconstruct that winter from things like tree rings and sediments or not. My guess is probably not.

“Oh man, this famine will be both great for my summer figure and for my job security as all of the old people die off.”

If you're talking about a mega eruption (VEI 7+) or a mega earthquake just in our region the earthquake is certainly much more likely. Everyone always talks about the big subduction quake, but for Seattle the next Seattle fault quake is the thing to really dread. That is overdue by a factor of about 3 now. I would say it's a toss up whether a VEI 7+ eruption will happen somewhere on the planet or a very major quake here will happen first. If you're talking about a super volcano (VEI 8 ) then the big quake will very likely happen here first.

The earthquake. @joelgombiner can speak better to this, but in the Seattle area we have multiple faults that cross the Puget Sound that are at various stages of “due” and “over due”, the two that make me raise an eyebrow are the ones that cut Whidbey and Bainbridge east to west and have histories of quakes at the 7-8 range. The Bainbridge (and West Seattle) fault have had a regular history of violent uplifts of several feet at a time. Then there is the subduction zone that is about due for something, either a partial slip or a full rip and slip, but we are not completely overdue as there is evidence in far past that the window was 500+ years or more. If you really want to go down a rabbit hole, look into episodic tremor and slip (ETS). With ETS, you can effectively see the plate move and subduct underneath in on a day-by-day basis. There are some interesting theories in how we might be able to use ETS swarms and periods of inactivity as a way to forecast deep earthquakes or even the much feared Cascadia quake. Yellowstone on the other hand is probably not going to burp for another 200,000 years and will most likely be smaller than its previous eruptions as there is ample evidence that the hot spot has been on the decline for the last 600,000 years. If people are rooting for a volcano, find something in the tropics that could produce a VEI-6+, have a high sulfur and water content, and will erupt between March and May. Sure, there will probably be a period of intense food stress if not outright famine, cost many lives, and maybe cause a global crisis that we haven’t seen in 200 years, but at least we’ll have a few snowy days in both December AND January.

60/47 IMBY today. The below normal days are really racking up now.