Warming seas double snowfall around North America's tallest peaks

Warming seas double snowfall around North America's tallest peaks
Time series shows the dramatic doubling of snowfall around North America's highest peaks since the beginning of the Industrial Age. Inset shows summer (red) and winter (blue) snowfall since 1870. Credit: Figure provided by Dominic Winski.

December 19, 2017 - Snowfall on a major summit in North America's highest mountain range has more than doubled since the beginning of the Industrial Age, according to a study from Dartmouth College, the University of Maine, and the University of New Hampshire.

The research not only finds a dramatic increase in snowfall, it further explains connections in the global climate system by attributing the record accumulation to warmer waters thousands of miles away in the tropical Pacific and Indian Oceans.

The research demonstrates that modern snowfall in the iconic Alaska Range is unprecedented for at least the past 1200 years and far exceeds normal variability.

"We were shocked when we first saw how much snowfall has increased," said Erich Osterberg, an assistant professor of earth sciences at Dartmouth College and principal investigator for the research. "We had to check and double-check our results to make sure of the findings. Dramatic increases in temperature and air pollution in modern times have been well established in science, but now we're also seeing dramatic increases in regional precipitation with ."

According to the research, wintertime snowfall has increased 117 percent since the mid-19th century in southcentral Alaska in the United States. Summer snows also showed a significant increase of 49 percent in the short period ranging less than two hundred years.

The research, appearing in Scientific Reports, is based on analysis of two ice cores collected at 13,000 feet from Mount Hunter in Denali National Park. According to the authors, accumulation records in the separate samples taken from just below the summit of the mountain known as "Denali's Child" are in nearly complete agreement.

"It is now glaringly clear from our record that modern snowfall rates in Alaska are much higher than natural rates before the Industrial Revolution," said Dominic Winski, a research assistant at Dartmouth and the lead author of the report. "This increase in precipitation is also apparent in weather station data from the past 50 years, but ice cores show the scale of the change well above natural conditions."

Once the researchers established snowfall rates, they set out to identify why precipitation has increased so rapidly in such a short amount of time. Scientific models predict as much as a 2 percent increase in global precipitation per degree of warming because warmer air holds more moisture, but this could not account for most of the dramatic increases in Denali snowfall over the studied period.

The research suggests that warming tropical oceans have caused a strengthening of the Aleutian Low pressure system with its northward flow of warm, moist air, driving most of the snowfall increases. Previous research has linked the warming tropical ocean temperatures to higher greenhouse gas concentrations.

The analysis includes a series of dramatic graphs that demonstrate extreme shifts in precipitation and reinforce the global climate connections that link snowfall in the high reaches of the North American continent with warm tropical waters. As noted in the paper, this same atmospheric connection accounts for a decrease in Hawaiian precipitation.

"Everywhere we look in the North Pacific, we're seeing this same fingerprint from warming tropical oceans. One result is that wintertime climate in the North Pacific is very different than it was 200 years ago. This doesn't just affect Alaska, but Hawaii and the entire Pacific Northwest are impacted as well," said Winski.

The research builds on a recent study using the same ice cores that showed that an intensification of winter storm activity in Alaska and Northwestern Canada, driven by the strengthening Aleutian Low, started in 1740 and is unprecedented in magnitude and duration over the past millennium. The new record shows the result of that increase in Aleutian Low storm activity on snow accumulation.

For this analysis, researchers were able to segment the ice core records by seasons and years using markers like magnesium from spring dust to separate winter snow from summer snow. To account for snow layers getting squeezed and thinned under their own weight, the researchers applied four separate equations used in other studies, and in all cases the corrected record shows at least a doubling of snowfall.

According to the paper, while numerous snow accumulation records exist, "to our knowledge, no other alpine ice core accumulation record has been developed with such a thorough characterization of the thinning regime or uncertainties; all of the thinning models produce a robust increase in accumulation since the mid-19th century above late-Holocene background values."

The researchers note that the findings imply that regions that are sensitive to warming tropical ocean waters may continue to experience rain and snowfall variability well outside the natural range of the past millennium.

"Climate change can impact specific regions in much more extreme ways than global averages indicate because of unexpected responses from features like the Aleutian Low," said Osterberg. "The Mount Hunter record captures the dramatic changes that can occur when you get a double whammy from climate change - warming air combined with more storms from warming ocean temperatures."

However, the researchers also note that the regional findings do not necessarily mean that the same level of snowfall increases will occur elsewhere throughout the mid- and high latitudes.

"Scientists keep discovering that on a regional basis, climate change is full of surprises. We need to understand these changes better to help communities prepare for what will come with even more carbon dioxide pollution in the air," said Osterberg.

As part of the analysis, the authors suggest that current climate models underestimate the sensitivity of North Pacific atmospheric connections to warming tropical ocean temperatures. They argue that refining the way the modeled atmosphere responds to tropical ocean temperatures may improve rain and predictions in a warming world.


Explore further

Severity of North Pacific storms at highest point in over 1,200 years

More information: Dominic Winski et al, Industrial-age doubling of snow accumulation in the Alaska Range linked to tropical ocean warming, Scientific Reports (2017). DOI: 10.1038/s41598-017-18022-5
Journal information: Scientific Reports

Provided by Dartmouth College
Citation: Warming seas double snowfall around North America's tallest peaks (2017, December 19) retrieved 23 July 2019 from https://phys.org/news/2017-12-seas-snowfall-north-america-tallest.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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Dec 19, 2017
That is good news for our local ski resorts. :)

Dec 19, 2017
Hallejulia the glaciers are saved!!

Dec 19, 2017
Hallejulia the glaciers are saved!!


*sigh* You really don't understand the climate system at all, do you?

Dec 19, 2017
Hallejulia the glaciers are saved!!


*sigh* You really don't understand the climate system at all, do you?
Whats really sad is when people are born w/o no sense of humor *sigh*

How come theyre always libtards I wonder?
https://www.youtu...DWLOolUs

-We'll fix your disease. Some day.

Dec 19, 2017
Hallejulia the glaciers are saved!!


*sigh* You really don't understand the climate system at all, do you?
Whats really sad is when people are born w/o no sense of humor *sigh*

How come theyre always libtards I wonder?
https://www.youtu...DWLOolUs

-We'll fix your disease. Some day.


First of all, as I've mentioned repeatedly, calling me a Liberal just reinforces your ignorance of socio-political categories. I am a social democrat, not a liberal democrat. A Liberal is a centre right political philosophy. I am centre left. I know that the US has no left-wing political parties but that doesn't excuse your ignorance of socio-political history.

Secondly, I fail to see the "humour" in your comment. Maybe that's my lack of humour but mostly it's because your comment was dumb. Unless I'm missing the punchline where glacier health and current regional snowfall have any relationship with each other.


Dec 19, 2017
...
Unless I'm missing the punchline where glacier health and current regional snowfall have any relationship with each other.

THAT was the point....

Dec 19, 2017
"I know that the US has no left-wing political parties but that doesn't excuse your ignorance of socio-political history."

OMG now THAT is funny. If the democrats were any more left they would circle back to the right because of the curvature of space.

Dec 19, 2017
"I know that the US has no left-wing political parties but that doesn't excuse your ignorance of socio-political history."

OMG now THAT is funny. If the democrats were any more left they would circle back to the right because of the curvature of space.


The Democrats are a liberal democratic party. This is centre right wing.

Dec 20, 2017
deleted

Dec 20, 2017
I am beginning to understand climate science. Every earthly change be it weather, social, health or financial is due to CO2 induced climate change. Without increased CO2 there would be no change. You are overselling this boys, overselling it to the point that even the liberals might catch on eventually. But it does not matter does it since you will have solidified your political power by then.

Dec 20, 2017
I am beginning to understand climate science. Every earthly change be it weather, social, health or financial is due to CO2 induced climate change. Without increased CO2 there would be no change. You are overselling this boys, overselling it to the point that even the liberals or EU conservatives, in deference to Lee, might catch on eventually. But it does not matter does it since you will have solidified your political power by then.


Dec 20, 2017
Mackita nice link but the data really does not matter since it was not published by a media outlet that is approved by the Ministry of Truth.

Dec 20, 2017
Your link, https://realclima...he-data/

illustrates the exact reason climate science is in no real rush to add more climate stations. The existing ones are accepted as needing "adjustments" and as such are much more useful to the movement.

Dec 21, 2017
Whatever the denier WANT to believe is up to them. It doesn't stop the facts that the article puts forth; namely
"Climate change can impact specific regions in much more extreme ways than global averages indicate because of unexpected responses from features like the Aleutian Low, said Osterberg. "The Mount Hunter record captures the dramatic changes that can occur when you get a double whammy from climate change - warming air combined with more storms from warming ocean temperatures."


But we know the EPA and Scott Pruitt will ignore global warming (anthropogenic or not), climate change, and a slightly more uncomfortable warmth in the summer regardless of science, reason, or a body of science. For the current EPA leadership it's all about Screwyouism(tm) or FUism(R-KY) for short. And we all know how well Trump supporters loved to be screwed by their republican masters.



Dec 22, 2017
"MR166
deleted"

Oh how I wish you were.

Dec 22, 2017
""Climate change can impact specific regions in much more extreme ways than global averages indicate because of unexpected responses from features like the Aleutian Low, said Osterberg."

What a redundant statement. Climate science has pretty much already stated that EVERYTHING can be caused by climate change or really AGW. This is an unfalsifiable "science".

Now that it has morphed into change even cooling is possible.

Dec 22, 2017
They are even claiming that AGW is the cause of the unrest in the Middle East when we all know the funding of terrorists and overthrow of governments was done purposely to induce migration.

Dec 22, 2017
What was started by Bush I and II was mastered by Obama when he funded ISIS and the other terrorists. The deep state in the US reached, I hope, it's peak power under Obama. We shall see won't we.

Dec 22, 2017
"Scientific models predict as much as a 2 percent increase in global precipitation per degree of warming because warmer air holds more moisture, but this could not account for most of the dramatic increases in Denali snowfall over the studied period."

.......and goody goody gumdrop, this will ensure that we will continue to have good trout & salmon fishing all up & down the Western USA coastal rivers & steams. Then maybe someday China & India will finally figure out that their polluted cities are enhancing climate change to the benefit of the USA & go on a serious counter offensive, but nah, they'll never figure that out & Trump will continue to run rings around their nanny-state politicians

Dec 22, 2017
Be rest assured, what ever happens in the future there will be some model created that retroactively proves it is due to CO2 levels.

Dec 22, 2017
"Scientific models predict as much as a 2 percent increase in global precipitation per degree of warming because warmer air holds more moisture, but this could not account for most of the dramatic increases in Denali snowfall over the studied period.""

So let me see if I understand the correctly. As the earth warms more clouds are created which reflect back into space more of the suns energy, cooling the planet. Wow that sounds suspiciously like a self-regulating system. As an added benefit vegetation grows better due to higher CO2 levels and more rain. OH THE HORROR OF IT ALL!!!!!!


Dec 22, 2017
As the earth warms more clouds are created

Actually that is not true. Clouds usually form on cold air when the water in the atmosphere condenses. Actually the water content of the atmosphere can increase (and does) without additional cloud coverage. However the water content stored is much larger and when it does precipitate out, it is trending to much larger rain amounts.

Where you can see global warming's effects are the very high cirrocumulus clouds where the additional global warming pushes water vapor to abnormally high regions, Look up sometime, and you might see more and more of the cirro formations, a direct consequence of global warming. When I was a kid, we never saw those high clouds except on a rare occasion. Now they are everyday and common.

Dec 22, 2017
"Actually that is not true. Clouds usually form on cold air when the water in the atmosphere condenses."

What goes up must come down Howhot. Before it comes down it must form clouds. This process also moves a lot of heat into the upper atmosphere where it is radiated into space as in self-regulating.


Dec 22, 2017
Of course, we all know clouds are water vapor. But the concentration of water in the air does not determine cloud cover, so a change in the albedo of earths reflectance to the solar input isn't going to change much. That stuff is already in the computer models of global warming anyway.

All I wanted to say to the deniers out there, is if you want a real measure of global warming, keep your eye on the sky for the next couple of years. Then you can see for yourself what is really going on.

Dec 23, 2017
"But the concentration of water in the air does not determine cloud cover, so a change in the albedo of earths reflectance to the solar input isn't going to change much. "

"Where you can see global warming's effects are the very high cirrocumulus clouds where the additional global warming pushes water vapor to abnormally high regions, Look up sometime, and you might see more and more of the cirro formations, a direct consequence of global warming. When I was a kid, we never saw those high clouds except on a rare occasion. Now they are everyday and common."

Well which is it there Mr. Hot? Unless the atmosphere is going to store an infinite amount of water vapor there will be more clouds and rain with increased temps since it does not rain without cloud formation!!!!

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