PORTLAND, Ore. — The term "atmospheric river" is becoming more common these days. It is a weather phenomenon used to be called a "pineapple express." No matter how it's referred to, one thing is for sure, these systems carry a lot of landslide-causing rain.
For decades, Portland State University geology professor Scott Burns has tracked hundreds of landslides across the Portland metro area. He even keeps track of slides happening globally. He found that many are the result of one specific weather event.
"Periodically we get these incredible rainfall events, but we're seeing more and more more of them," Burns said. "We are calling them atmospheric rivers."
Atmospheric rivers are very long bands of water vapor in the atmosphere that act like a pipe in the sky transporting huge amounts of water. That water then drops as intense rainfall.
"All of the models show that the climate is warming and with warming you're seeing more and more evaporation of water from the oceans and more water vapor in the atmosphere," Burns said.
The result of so much rain in such a short amount of time? Not only more, but bigger and more destructive landslides.
"We're seeing an increase in the number of landslides and the sizes and the people killed," Burns said. "Just last week in Pakistan, we had 20 people killed by a very, very large landslide."
Burns said, worldwide, the frequency of deadly landslides has greatly increased over the past 30 years. And the past six months have been notably bad.
"The number of people dying from landslides in the last six months has been incredible worldwide," he said.
And while these atmospheric rivers can't be avoided, the resulting landslides can be prevented in many cases.
Homeowners need to make sure their water collection systems are working, their gutters are working and that the water doesn't overflow onto and saturate the slope below.
Another reason to prepare for landslides now? Not only will there be more of them in the future, homeowners insurance does not cover them.
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