Juneau, Alaska, Hit With Another "Glacial Outburst" Flood, But This Time They Fought Back

Barriers this year kept the worst of what has become
the annual glacial outburst flood this week
in Juneau, Alaska. You can see how badly
the houses in this photo would have been
flooded without the barriers. 

 Yearly summer events are often fun.

'The one in Juneau, Alaska is not.  

Once again, as has happened every August lately, parts of Alaska's capitol city are being hit by what is know as a glacial outburst flood. 

Such a flood happens when parts of a glacier melt, and water backs up behind rocks and/or ice. Finally the water breaks through, causing an often destructive flash flood. 

In Juneau, water from the melting glacier fills a hemmed in basin until the pressure grows strong enough to release a torrent of water from the Mendenhall Glacier and down the Mendenhall River into Juneau. 

Per the Washington Post: 

"By Wednesday morning, the floodwaters racing gown from what's called Suicide Basin has risen to record levels, faster than scientists had predicted the day before. 

Juneau officials warned residents to evacuate parts of the city that have been prone to repeated flooding."

It appears the flooding peaked Wednesday morning.    About 1,000 people had evacuated ahead of the flood. 

The Mendenhall River was already at minor flood stage because of heavy rains Sunday and early Monday. Since the river started at an elevated level, the gush of water from the glacier pushed the river Wednesday morning to 16.65 feet, which surpassed the record high level of 16 feet set during last August's glacial outburst.  

Since this has become a destructive, frustrating annual event, Juneau is trying to minimize the damage. 

This year, the city worked with the U.S. Army Corp of Engineers to build a massive wall of Hesco barriers along the river to prevent the destruction seen in the last two years, WaPo reports. 

Hesco barriers are durable cloth bags filled with dirt and sand and reinforce with a metal frame. They were often used by the military in places like Iraq and Afghanistan to fortify bases.  But they can be used as giant sandbags, too.

Early reports suggest the Hesco barriers mostly held, preventing much of the feared damage to homes near the river. Roads and streets were inundated, and some homes might have taken on a little water, but the damage appears to be much less than in the previous two years. 

The Hesco wall is expensive, and included big bills assessed to residents who live in flood zones.  There needs to be a more permanent solution, but the future of these floods is unpredictable. 

 The Juneau glacial outburst floods started in 2011 and have worsened in recent years. Climate change is helping to melt more glacial ice than in years past, so more water is now usually available to cause these August floods.

In August, 2023, the outburst flood destroyed several homes.  That event included dramatic video of a house collapsing into the river.  Last year, at least 300 homes were damaged by the flooding. 

It's possible that the nature of future summer glacial floods could change as more of the glacier melts, or the thawing gets even more intense in future years. Alaska has warmed twice as fast as any other state over the past few decades, and there's no reason why that trend won't continue, as areas closer to the Arctic are warming faster than places closer to the Equator. 

The Mendenhall glacial flooding could in upcoming years find another outlet, or burst out another way instead of blasting down the Mendenhall River in one big swoosh.  

Juneau - and many other parts of the world prone to glacial outburst floods in the age of climate change - need to stay on their toes. 

Climate Change MIGHT Have Contributed To Massive Swiss Glacial Collapse; Is Causing Other Glacier Crises

A massive avalanche of ice, rocks and other glacial
debris roads down the slopes  in the Swiss Alps in 
late May, ultimately burying most of a village.
Many scientists think climate change 
contributed to the massive collapse. 

 You might have seen dramatic video on the news at the end of May of what appears to be an entire mountain crashing down on what was a tiny, picturesque Swiss village, burying it in mud, rocks debris and water.  

What hit was a glacial collapse in the Swiss Alps.

It began when a rock slope above the glacier began to crack and fall apart, depositing rocks atop the glacier.  

Swiss emergency officials noticed this development unfolding. It alarmed them enough to evacuate Blatton, the village that was eventually 90 percent buried by the debris flow.

On May 28, either the glacier collapsed under the weight of the rocks accumulating on top of it, or more of the rocks above it suddenly slid, causing a chain reaction that sent new rocks, the accumulated rocks and most of the glacier roaring down the mountainside, mostly burying the village, 

Since Blatton had been evacuated ahead of the calamity, there is only one reported casualty.  A 64-year-old man was reported to be in the village when the glacier collapsed. 

The collapsed glacier dammed a river on the valley floor, forming a lake that flooded most of the houses that weren't directly hit by the glacier and landslide. Worries are growing the new lake will bust through the glacial debris, causing a flash flood downstream. 

The astounding glacial collapse set off debate as to whether and to what extent climate change caused or contributed to the calamity. 

 Per the Washington Post:

"Experts are mixed in their views over whether the collapse was caused by climate change. Christophe Lambiel, a geologist a the University of Lausanne, told Switzerland's national broadcaster that the glacier had previously been supported by a high rock face encased in permafrost, which had degraded over the past 10 to 15 years, putting pressure on the glacier.

He said climate change 'probably' played some role in the collapse."

Common Dreams also reports many climatologist and glaciologists suspect climate change played a role, and fear similar events loom in the future: 

"Mathieu Morlighem, a glaciologist at Dartmouth College in New Hampshire, told ABC News that permafrost thaw under and along the sidewalls surrounding the glacier likely caused the collapse.

'What happened to the Birch Glacier is what we would expect from rising temperatures in the Alps and elsewhere, he explained. 'I think we can expect more events like this in the future.'"

More study is going to be needed to what extent climate change influenced the May glacial collapse in Switzerland.

But melting glaciers and permafrost in the mountains and Arctic regions are threatening new disasters. 

For instance, melt water can collect behind ice in a glacier, then suddenly break through, causing catastrophic downstream floods. That happened last summer in Juneau, Alaska, when a so called "glacial lake" formed behind ice on a glacier

That lake eventually abruptly broke through, causing a record-setting flood along the Mendenhall River, flooding at least 300 homes.

These so-called outburst floods have always occurred. But these  outburst floods are an increasing threat in Alaska, the Andes, Himalayas, European Alps, Iceland and Alaska due to the added melting brought on by climate change. 

Mountain  glaciers also supply critical water supplies for as many as 2 billion people worldwide. Over the course of centuries, bits of glaciers would melt in the summer, only to start building back up in the winter. 

Now, they're melting faster than they can rejuvenate. Which is why you get these glacial collapses and glacier outbursts. There's just too much water and melting all at once. 

Eventually, though, the glaciers will disappear, erasing sources of drinking water and especially agricultural irrigation.

This is all just one more worry created by climate change.  If mountain glaciers become unstable, so do regional societies, and public safety.  Every time I turn around, it seems, I notice another negative effect of climate change.  

VIDEO

Worth seeing again as it's so spectacularly awful. Video shows the mass of rock, ice and other debris roaring down the slopes of the Swiss Alps in late May. Click on this link to view, or if you see the the image below, click on that.

Is Climate Change Making Days Longer, Slowing Earth's Rotation?

 Apparently, Earth is spinning more slowly than it used to because of climate change.

Earth's rotation has slowed down ever so slightly, due
to, believe it or not, climate change.

It's definitely not slow enough for you to notice it, though. 

It does turn out that melting ice from glaciers and ice caps and such are messing up the Earth's rotation just a little bit.  

According to Nature.com:

"An analysis published in Nature ......has predicted that melting ice caps are slowing Earth's rotation to such an extent that the next leap second - the mechanism used since 1972 to reconcile official time from atomic clocks with that based on Earth's unstable speed of rotation - will be delayed by three years.

'Enough ice has melted to move sea level enough that we can actually see the rate of the Earth's rotation has been affected,' says Duncan Agnew, a geophysicist at the Scripps Institution of Oceanography in La Jolla, California and author of the study."

This is all being looked into by metrologists, who are scientists who study measurements, not to be confused with meteorologists, who study weather. 

Precision timing via atomic clocks means every once in awhile adjustments need to be made to match the Earth's rotation. 

Probably due to changes in the Earth's core, the planet's rate of rotation had been increasing a little since the 1970s or so. That has made those occasional leap seconds necessary.

The world-wide bodies that keep track of this sort of thing had scheduled a "leap second" in 2026.  But since the Earth's rotation is now that itty bitty bit slower than it used to be, the leap second has been postponed to 2029.

You wouldn't think Earth's rotation slowing by such a minuscule amount would matter to you and me, but it turns out it does.

Nature.com explains: 

"A delayed leap second would be welcome by metrologists. Leap seconds are a 'big problem' already, because in a society that is increasingly based on precise timing, they lead to major failures in computing systems, says Elizabeth Dooley, who heads the time and frequency division at the National Institute of Standards and Technology in Boulder, Colorado. "

So, in this case, climate change is doing people a favor, for a change. Obviously the bad greatly outweighs the good, but I suppose there's a bright side to everything.

For now anyway. 

If the Earth's rotation slows enough to require a negative skipped second rather than one being added, it would create a nightmare. There's no accounting for it in all the existing computer codes, so nobody is sure how to make a negative second work.

We should also probably explain why melting glaciers and such are making the Earth's rotation slow down. To understand, it try to think of Earth as a figure skater. 

Nature.com gets into it:

"Data from satellites mapping Earth's gravity show that since the early 1990s, the planet has become less spherical and more flattened, as ice from Greenland and Antarctica has melted and moved mass away from the poles toward the Equator.

Just as a spinning ice skater slows down by extending their arms away from their body (and speeds up by pulling them in), this flow of water away from Earth's axis of rotation slows the planet's spin."

Climate change is why metrologists are worries about "negative leap seconds."  As more and more ice melts from Greenland and Antarctica, the Earth's slowdown will probably continue. 

Scientists plan to eliminate leap seconds in 2035 in favor of much less frequent leap minutes. Leap seconds are just not worth the trouble.