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Why Is the Pacific Northwest So Rainy?

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The Pacific Northwest is home to some of the most breathtaking scenery in the United States, but that greenery comes at a cost. It rains in the Pacific Northwest, and it rains a lot. Despite the gorgeous landscapes and cosmopolitan cities, the western parts of Washington and Oregon get a bad rap for how gray and dismal they can be. But why exactly does it rain so much in the Pacific Northwest?

The reason gloomy weather is so common boils down to prevailing weather patterns and the unique terrain that makes this part of the world so gorgeous. This stretch of land between Portland, Oregon, and Seattle, Washington, usually finds itself directly under the track of the jet stream. The jet stream is a fast-moving river of air that encircles the Northern Hemisphere right around the latitude of the U.S.-Canadian border.

Whenever the jet stream swoops to the south, creating a trough, it can generate low-pressure systems at the surface that produce heavy rain and high winds. These troughs and resulting low-pressure systems often intensify in the Gulf of Alaska and over the Pacific Ocean off the coast of Washington, allowing large storms to crash into the coast with ease. Most of these storms are run-of-the-mill rainmakers, lasting for a day or two before moving on, but some of them can be enormous and cause significant wind damage and flooding.

While the photogenic low-pressure systems that swirl into the coast are the driving force behind the Pacific Northwest’s seemingly endless rains, it’s the region’s terrain that locks in those dismal weather conditions. When moist winds blow inland with an approaching storm, the high terrain of the Cascade Range forces the moist air to rise into the atmosphere, enhancing the thick clouds and steady rainfall.

Rain clouds over Pacific Northwest
Cloudy skies over the Pacific Northwest on May 16, 2017.

Even though it rains quite a bit along the northwestern coast, actual rainfall totals in the Pacific Northwest vary wildly from place to place due to changes in elevation. Some spots at high elevation right along the coast or along the Cascade Range can see more than 10 feet of precipitation in a single year, accounting for both rain and the equivalent amount of liquid in snowfall.

Seattle, Washington, and Portland, Oregon, each only see around 36 inches of rain every year, which hardly makes these bustling metro areas the wettest in the country. Compare their rainfall totals to New York City’s Central Park, which measures nearly 50 inches of rain every year, and Mobile, Alabama, commonly one of the wettest cities in the United States; its proximity to the Gulf of Mexico gives it nearly 66 inches of rain every year.

The rain that does fall in Seattle and Portland, though, falls over a longer period of time. Between 1981 and 2010, both cities saw a little more than 150 days with measurable precipitation per year, compared to about 122 rainy days in New York City and just 115 in Mobile. This accounts for the Northwest’s reputation as the gloomiest part of the country—but makes for spectacularly green landscapes when the skies clear out.

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Weather Watch
It Just Snowed In the Sahara for the Second Time In Less Than a Month
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The town of Aïn Séfra, Algeria might need to find a new nickname. Though it’s often referred to as “The Gateway to the Sahara,” the 137-year-old province in northwest Algeria is currently digging out from a rare—and unexpected—snowstorm that left the desert town covered in several inches of snow and battling sub-zero temperatures.

While the Daily Mail reported that “locals took to the nearby sand dunes to enjoy the unusual weather,” the strangest part of the story is that this is Aïn Séfra’s second snowfall in less than a month. On Sunday, January 7, a freak blizzard left parts of the Sahara blanketed in as much as 16 inches of snow.

This most recent storm marked the region’s fourth snowfall in nearly 40 years; in addition to January's dose of the white stuff, the area has been hit with other surprise wintry events in February 1979 and December 2016.

But North Africa isn’t the only area that’s seeing record-breaking weather events. On Saturday, February 3, 17 inches of snow fell on Moscow within 24 hours in what the country has dubbed “the snowfall of the century.” In mid-January, Oymyakon, Russia—a rural village in the Yakutia region, which is already well known as one of the coldest inhabited areas of the world—saw temperatures drop to -88.6°F, making it chilly enough to both bust thermometers and freeze people’s eyelashes. And you thought dealing with single-digit temperatures was tough!

[h/t: Daily Mail]

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Weather Watch
Record-Breaking 17 Inches of Snow Covers Moscow in 24 Hours
Vasily Maximov, AFP/Getty Images
Vasily Maximov, AFP/Getty Images

Moscow sees some of the most brutal winters of any world capital, but even locals weren't prepared for the most recent winter storm to batter the city. As Newsweek reports, a record-breaking 17 inches of snow buried Moscow within 24 hours.

Roughly 7 inches of snow fell just on Saturday, February 3, and the deluge continued through the following Sunday. The accumulation has already been dubbed the "snowfall of the century," and officials expect up to 3 additional inches to cover the ground over the next three days.

The sudden blizzard has brought life to a stand-still in the metropolis of 12 million. The mayor is warning motorists to stay off the roads as around 15,000 snowplows clear the snow. About 2000 trees have been toppled by the storm, injuring at least five people and killing one.

Even as the worst of the weather winds down, over 40,000 people in Moscow and the surrounding regions are without power. Meanwhile, traveling in and out of the city has become close to impossible: Around 100 flights are grounded at the local airport indefinitely and at least 10 have been canceled all together.

The historic snowfall hasn't stopped many of Moscow's tougher residents from venturing outside. Check out photos from the event below.

Person cross-country skiing over snow in Moscow.
Yuri Kadobnov, AFP/Getty Images

Walking through a blizzard in Moscow.
Yuri Kadobnov, AFP/Getty Images

Walking through the snow in Moscow.
Yuri Kadobnov, AFP/Getty Images

Walking through the snow in Moscow.
Yuri Kadobnov, AFP/Getty Images

[h/t Newsweek]

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