Facing climate change: Jet stream instability causes record rainfall, summer flooding of Lake Champlain

LakeChamplainLevels2013Persistent afternoon thunderstorms have battered northern Vermont’s farms, washed out roads, and brought Lake Champlain to record levels over the last few weeks. The high waters of Lake Champlain, unprecedented at this time of year, can be linked to climate change, scientists say.

“With the data and with the research, you can say that this weather pattern we have right now is definitely the fingerprint of climate change,” said Roger Hill, a consulting meteorologist who does weather forecasts for utilities in the state as well as several radio stations.

The weather pattern Hill is talking about is a mass of moist, tropical air from the Gulf of Mexico that has been forced up into the Northeast by a high pressure zone over the western United States, another high pressure zone over the Atlantic, and a low pressure trough over the central United States. The Bermuda High, the zone over the Atlantic, blocks weather patterns from moving east, away from Vermont.

“That trough that’s off to the west over the U.S. is what’s unusual—to lock in and stay there for such a long period of time,” said Hill. Typically, the jet stream moves in short waves, perhaps the size of Montana and Wyoming, across the United States, and it does so relatively quickly. “But what’s happening is the big, long meandering jet stream that snakes way down into the Gulf of Mexico from Canada, it picks up that tropical moisture and displaces it way north. That’s what’s making the weather crazy. And it’s stuck, it can’t get anywhere.”

On July 4, the water level in Lake Champlain exceeded the all-time record for that day, topping out more than three feet above average at 99.38 feet, as recorded at the King Street dock in Burlington. Since then, the water rose to a record 99.64 feet on July 8 before declining slightly—but still breaking records—at 99.59 feet on July 10. The National Weather Service has been keeping records there since 1908.

Conor LaHiff is a meteorologist at Burlington’s National Weather Service office. He agreed that this weather pattern is unusual. “The amount of time it’s spent over us is abnormal. We’ve been in this airmass for two weeks at this point.”

Perkins Pier on Burlington. Photo courtesy of Lake Champlain Basin Program.

Perkins Pier on Burlington. Photo courtesy of Lake Champlain Basin Program.

The last time the lake flooded was in the spring of 2011. The Lake reached its highest recorded level at 103 feet and caused widespread damage in Quebec and in communities along the lake in New York State and Vermont. Estimated road damage in Vermont alone was $6 million.

“Typically during the spring months — anywhere from the mid part of March to mid-June—Lake Champlain is at its highest and that’s due to snowmelt and spring showers,” said LaHiff. Then the lake level falls throughout the summer. “The difference this year is that we’ve had record levels of rainfall across the state and parts of New York for both May and June, which have kept that water level abnormally high.”

Vermont has had more than 11 inches of rain above average for May and June. The two months are the wettest consecutive 30-day periods on record for Vermont.

“If you go back 30 or 40 years, we had weather patterns where, typically, our fronts would pass us every five days or so and there would be a strong flow from west to east,” said Alan Betts, an independent climate researcher based out of Pittsford who is a consultant for NASA and the National Oceanic and Atmospheric Administration. “But if you look at the last few years, there’s been a pattern where the amplitude of the jet stream has got stronger and the jet stream has been moving more slowly from west to east. That has changed how long periods of no rain or periods of rain remain over us.”

Sunset over Lake Champlain, stockxchng.com

Sunset over Lake Champlain, stockxchng.com

LaHiff said July 13 was the start of a drier period as the Bermuda High breaks down and the low-pressure trough moves into our region. He said we could still see some rain, but the humidity will drop.

“The way to think about jet streams and frontal systems and storms is that broadly speaking the tropics are warm and the Arctic is cold,” said Betts. “These global weather patterns are transporting heat and they’re transporting water from the tropics further north, trying to keep the earth in some sort of energy balance—and they do. But as the Arctic is melting and getting warmer, that gradient of temperature between the tropics and the Arctic is getting less. It appears that the northern hemisphere climate patterns, patterns of the jet stream, are changing as well, and that’s affecting how our climate is changing.”

A 2012 Rutgers University study led by Dr. Jennifer Francis found that the jet stream, a current of high-altitude air that curves across the northern hemisphere, is becoming unstable, curvier, and slower. The result is an increase in extreme weather events that stay in place longer, such as persistent storms that cause flooding, or long-lasting drought. Francis found connections between anomalies in the jet stream and a number of extreme weather events throughout the world.

“It’s why we’ve had 500-year floods in Europe. It’s why Calgary had the biggest floods in the history of Canada,” said Hill. “It’s happening all over the world and it’s all related to these weather patterns that are meandering.”

LaHiff is not so certain, though he agrees the Rutgers study is convincing. “It’s not a definitive answer as to why some of this stuff is happening,” he said, “but it certainly does make sense.”

Audrey ClarkAudrey Clark

Audrey Clark writes articles on climate change and the environment for VTDigger, including the monthly column Landscape Confidential. After receiving her bachelor’s degree in conservation biology from Prescott College in Arizona, she worked as a field ecology research assistant and college teaching assistant for five years. Read more

Email: [email protected]

Latest stories by Audrey

Comments

  1. Jim Barrett :

    When the weather people can’t predict the weather for the next 5 days accurately, I don’t place much confidence in this report. The weather has been changing for millions of years without man made injections of something bad and it will change long after we are all gone.

    • Townsend Peters :

      Now that’s a silly comment.

      The article doesn’t actually state that human activity caused Vermont’s rainy season this year. It just quotes people who link it to “climate change,” cause not specified.

      And yes, the weather changes all the time. But the issue is _climate_ not weather.

    • Steve Comeau :

      Jim,
      It is true that the climate “has been changing for millions of years without man made injections of something bad …”. But, that really is not the issue. Now, and for the past 100 years or so, we do have large scale “man made injections of something bad“, which is causing the climate to change quickly and with greater intensity than natural variation. A very slow warming over centuries would be fine, but the man induced climate change is happening quickly and may be changing the global wind patterns in unpredictable ways, which is a cause for concern.

  2. Kai Mikkel Forlie :

    For the four or five people out there still not convinced that anthropomorphic (human induced) climate change is real, I suggest this recent talk given to meteorologists by Rutgers research professor Jennifer Francis:

    http://www.youtube.com/watch?feature=player_embedded&v=ETpm9JAdfcs

    …and also Richard Heinberg’s book “The End of Growth”.

    And for those out there profiting by offering up “plausible deniability” on forums and in letters to the editor, etc., please stop. At this point you’re just embarrassing yourselves.

  3. James Maroney :

    I have been reading Judith Schwartz’s book “Cows Save the Planet” Chelsea Green 2013. She describes how photosynthesis uses the energy from sunlight to combine water and CO2 to make sugar which pulls carbon out of the atmosphere and deposits it in the soil. The opposite process, respiration, causes carbon to oxidize out of the soil into the atmosphere (I vaguely knew this from 10th grade biology). What I did not know is how big a system this is; we are told over and over that global warming is caused by our insatiable appetite for burning fossil fuels. But she says that if we (the whole world) were able to reduce emissions from the burning of fossil fuels to zero but did not change the way we farm (overwhelmingly conventional, which pulls carbon in the form of oil stored in the earth over millenia which we burn, and puts it into the atmosphere) atmospheric carbon would still rise. I have been pushing organic agriculture as the solution to farm attrition and lake pollution and organic farming does build soil. But this adds a new angle: switching from conventional to organic farming could also reverse global warming. The beauty of it is that there is no downside, no negative message in this approach. Just change the way we farm.

  4. Rob Simoneau :

    There are two critical issues here, climate change and habitat destruction. Both have serious consequences for the world population and our environment. Both must be recognized understood and addressed. The creation of acids continue to “burn” trees and vegetation as well as pollute our water and ground. In addition the increase of neurotoxins such as mercury increases is extremely dangerous in our food chain. If you want a global analysis of habitat destruction that is being done I refer you to reports generated by the United Nations, please look at the Geo 5 or the earlier version:

    Geo 5, all the reports can be found on
    http://www.unep.org/geo/GEO5_Products.asp

    Geo 4 Executive Summary
    http://www.unep.org/geo/geo4/media/GEO4%20SDM_launch.pdf

    or the entire Geo 4 entire text
    http://www.unep.org/geo/geo4/report/GEO-4_Report_Full_en.pdf

    If you take Glad Clingwarp and cover a baseball that would pretty much represent our atmosphere for Earth. Please remember there is no planet B.

Comments

*

Comment policy Privacy policy
Thanks for reporting an error with the story, "Facing climate change: Jet stream instability causes record rainfall,..."