Most Of Eastern Two-Thirds Of United States Had Incredibly Wet 2018.

Record spring rains in 2011 sent waves from a flooding Lake Champlain
crashing onto Route 2 in North Hero, Vermont. 

Up here in northern Vermont, it has only been a slightly wet 2018. In Burlington, for example, there had been a grand total of 37.13 inches of rain and melted snow and ice through December 12th. That's about an inch and three quarters wetter than normal.

Not a big deal, really. With only half a month to go in 2018, we won't come remotely close to the record wettest year, which was 2011, with 50.92 inches. We won't even come close to cracking the Top 10 wettest.  

We're an exception to the rule for much of the United States. Many places have been incredibly wet.

According to Climate Central:

"Of 2,800 stations analyzed by Climate Central, 133 (across 21 states) saw record precipitation totals this year, and 685 saw yearly totals that were among the top 10 on record. 2018 is already the fifth wettest year on record in the contiguous United States."

By the way, yes, I know Climate Central is an advocacy group that is trying to call attention to global warming and its effects. But the reporting here appears to me to be pretty solid. 

It's just normal to have a few places to report their wettest or driest year on record. There's always going to be extremes somewhere, that's just the way it goes.  

However, that so many places are having their wettest or close to their wettest year on record is indeed unusual. 

A great number of locations extending from the central Plains to the East Coast, with the exception of North Dakota, northern Minnesota and northern New England, have had an extraordinarily wet year. 

You can't blame one particular city's wet year on climate change, but when this sort of weirdness gets so widespread, you have to wonder.

THE SCIENCE BEHIND THIS

Warmer air holds more moisture. As the atmosphere warms, this added moisture can dump out in the form of heavier downpours than would occur in a cooler world.

Damage from flash flooding in Barre, Vermont during the record wet
year of 2011.

Dr. Jeff Masters at Weather Underground's Category 6 blog had an interesting tidbit on this subject recently. Says Masters:

"Preliminary research by precipitation expert Dr. Kenneth Kunkel of the North Carolina Institute for Climate Studies announced in September that the three highest-volume rainfall events for the U.S. in the last 70 years occurred since 2016."

Those events were Hurricane Harvey in 2017, Hurricane Florence earlier this year in North Carolina and a March, 2016 storm in Louisiana.

Adds Masters, echoing what I said above: "It is highly unusual to get three such extreme events in one three-year period, and the odds of this occuring were increased by global warming, which boosts the amount of water vapor in the air and increases the frequencey and intensityof heavy precipitation events." 

Only three of the Top 10 precipitation events over the past 70 years uncovered by this research occurred before 1994 - just 25 years ago or so.

Climate change skeptic Joe Bastardi acknowledges the increased water vapor in the air in a recent Patriot Post article, at least in how it played out in the nation during early December.

Atmospheric moisture has been generally quite high overall this month. This tends to make overnight low temperatures warmer, and afternoon high temperatures cooler. Sure enough,  nightime lows for the nation as a whole were warmer than normal in early December, while daytime highs have been mostly cooler than normal.  

Here's where Bastardi and climate scientists disagree. Bastardi says a narrower temperature range means less volatility. He also says the temperature gradient between the poles and temperate regions in the mid-latitudes has decreased with this atmospheric moisture, deceasing clashes and thus dangerous storminess.

However, many climate scientists are coming around to the idea that the subsiding contrast in temperatures between the poles and the mid-latitudes is screwing around with the jet stream, making it much wavier and prone to getting "stuck" in position. That would increase storminess, or at least increase weather extremes.

By the way, Bastardi attributes the increase in atmospheric water vapor not to greenhouse gases but the oceans. He said natural cycles temporarily increased overall water temperatures, which then increases water vapor in the Earth's atmosphere. The water vapor warms up our nights, so that's what's causing what he sees as a temporry increase in Earth's atmospheric temperature.

The vast majority of climate scientists agree that the increased water vapor in the atmosphere is created by warmer oceas. But the oceans are warmer because of  increased greenhouse gases in the atmosphere and the oceans won't cool noticeably through natural cycles. They'll just keep getting hotter.

DROUGHTS, TOO

Not everybody is wetter, of course.

Smoke from wildfires in the drought-stricken West helped create
this otherworldly sunset, as viewed from  St. Albans,
Vermont this past August 

With natural variability, often augmented by climate change, you can also get some serious and weird droughts in areas outside the "wet zones."

There were, of course, some weirdly dry sections of the nation as well. California and some other western states saw near record dryness in 2018, which helped fuel this year's extremely destructive wildfires in California. 

Also, parts of southeastern Alaska have "only" had 95 inches of rain this year. For most of the United States, that amount of rain would make things by far the record wetttest.

But southeastern Alaska is basically a rain forest (except for the mountain peaks, which of course are too high and too cold to support forests.)

The Weather Channel reports:

"Ketchikan, Alaska has recorded 96.62 inches of precipitation (rain/melted snow) in 2018 through December 10. In many parts of the United States, that would be an extreme amount, but in Ketchikan, that's 35.94 inches below average."

 It's going to be this Alaskan city's fourth driest year on record. 

Even in places that are extremely rainy, a shortage of precipitation like this can cause real problems.  Despite the heavy but still-subnormal rainfall, the region has been declared to be under a drought this year. 

According to the Weather Channel:

"The Metiakatla Indian Communityh on Annette Island was at risk of losing power after it had to stop hydroelectric power turbines due to low water levels. In early October, streamflows in the region were at much below to record low levels. 

Ketchikan had to switch to supplemental diesal fuel for power instead of cheaper hydroelectric power in late September."

It finally rained enough in November for Ketchikan to go back to hydroelectric power.

CIRCLING BACK TO CLIMATE CHANGE

Again, I want to be careful, because droughts have always happened. Areas of drought could easily be due to natural variability. It's a roll of the dice. One roll might give you a wet year, another might give you a dry year.

However, climate change might he weighing the dice to make one outcome more likely than the other. As Climate Central reports:

"Just as climate change has made heavy rainfall more common in some areas, so has it encouraged droughts in other. As temperatures continue to climb from increased greenhouse gas emissions, evaporation rates also increase. The higher evaporation rates dry out land surfaces faster, making droughts worse. Warmer temperatures can also cause more winter precipitation to fall as rain rather than snow, diminishing the store of snowpack whose slow melting many communities rely on for their water."

Up here in Vermont, we missed out on having an wicked wet year because a long-lasting weather pattern in the late spring and pretty much the entire summer steered moisture away from us 

Persistant high pressure off the East Coast and in southeastern Canada steered a steady flow of deep moisture up the East Coast, then steered it either westward or eastward a little south of us, so we missed out.

That same weather pattern created a lot of hot weather in our neck of the woods. The heat combined wth the relatively dry pattern triggered a drought over northern Vermont.

It took just two months of above normal precipitation in October and November to largely erase the drought. A wet early spring combined with the soggy late fall gave us our slightly wetter than normal 2018.

We are skewing wetter in Vermont, though. In Burlington, six of the top 10 wettest years have been since 1983. (Records go back at least to the 1880s). Meanwhile, all but one of the top 10 driest years in Burlington came before 1964. (The year 2001 made it into the Top 10.)

So in general, we might get our occasional Vermont drought, but for the most part, I see mostly wetter times ahead.