Plastered! Images from space show just how much snow has accumulated in large parts of the U.S. West

By Tom Yulsman | February 23, 2019 6:38 pm

Satellite images show how much more snowpack has accumulated in the Sierra Nevada mountains this year compared with last year. (Images: NASA Worldview. Animation: Tom Yulsman

What a difference a year makes.

After a shocking dearth of snow last year, the Sierra Nevada mountains of California and Nevada truly have been getting plastered, helping to build up the snowpack that millions of people depend on for water.

Other parts of the western United States have also benefited from a bounty of precipitation that has eased drought conditions. But does this herald a change in long-term fortunes in the region? Read on to the end for insights about that.

First, though, let’s focus on the headline-making parade of storms that have marched in from the Pacific. To fully grasp their impact, there’s no better perspective than the synoptic one available from space. With that in mind, I created the before-and-after animation of satellite images above. Read More

Just in time for Valentine’s Day, the ocean and atmosphere have coupled — giving birth to a weakling El Niño

By Tom Yulsman | February 14, 2019 1:20 pm
Weakling El Niño

Warm conditions along the equator in the Pacific Ocean in January are characteristic of El Niño. (Source: NOAA)

It’s finally here.

This morning, the National Oceanic and Atmospheric Administration made it official: El Niño conditions are present in the tropical Pacific Ocean. There’s a 90 percent chance that they’ll continue through winter, and a 60 percent chance through spring.

True to predictions, this El Niño is a weakling.

Climate scientist Emily Becker summarized the situation at the ever-awesome ENSO blog: Read More

CATEGORIZED UNDER: Climate, ENSO, select, Top Posts
MORE ABOUT: climate, El Niño, ENSO, weather

The U.S. climate became afflicted by split personality disorder in 2018

By Tom Yulsman | February 8, 2019 12:07 am

Meanwhile, the Earth as a whole continues to ride the up-escalator of human-caused global warming

2018: climatic split personality

2018 was the fourth warmest year on record globally, part of a decades-long warming trend. (Source: NASA Goddard Media Studios)

Two U.S. agencies have reported on how Earth’s climate fared in 2018. For the most part, the news wasn’t all that surprising: The long-term trend of human-caused global warming showed no significant signs of relenting.

But I was surprised by one finding: The United States experienced something of a split climatic personality last year.

More about that in a minute. First, though, NASA and the National Oceanic and Atmospheric Administration announced yesterday that Earth experienced its fourth warmest year in records dating back to the late 1880s.

“Across the globe it was extremely warm, with only a few places that were slightly below normal,” observed Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies, during a phone briefing with reporters that I participated in. The planet continues to warm over the long term, and “it’s because of the greenhouse gases we’ve put into the atmosphere in the last hundred years.” Read More

As Earth warms from human activities, brutal cold waves are becoming less severe, not more so

By Tom Yulsman | February 5, 2019 5:49 pm
Visualization of the late January outbreak of Arctic cold in the Midwest and Great Lakes

Visualized in this animation of GOES-16 weather satellite images is the outbreak of frigid Arctic air in the Upper Midwest and Great Lakes regions of the United States on January 29 and 30, 2019. In the false color scheme (characteristic of what’s known as ‘Air Mass RGB’ imagery), the coldest air is depicted in pale shades of yellow to beige. (Source: CIMSS Satellite Blog)

As brutal cold spilled out of the Arctic and enveloped much of the U.S. Upper Midwest and Great Lakes in late January, news stories tied the event to global warming. Here’s a sampling of headlines:

“Brace for the Polar Vortex; It May Be Visiting More Often” (NY Times)

“The Polar Vortex And How It’s Related To Global Warming (Forbes)

“Polar Vortex Linked to Climate Change (WGBH)

An increasing but still contested body of science suggests that rapid and intense warming in the Arctic actually is triggering changes in the jet stream that can affect weather far to the south. So these stories were accurate — as far as they went.

But as it turns out, intense Arctic cold snaps like the one at the end of January have become less widespread and common as the globe has warmed due to human activities, not more so. And so by downplaying or even leaving that key bit of context out, some of the coverage didn’t go far enough.

Consider the graphic below showing the change in unusually cold temperature in the contiguous 48 U.S. states between 1948 and 2015: Read More

Human-caused global warming already has doomed a large fraction of Earth’s glaciers

By Tom Yulsman | January 29, 2019 7:02 pm

But thereʼs a silver lining to this dark cloud: You can still make a personal difference in preserving glacial ice.

Glaciers doomed by global warming

A large chunk of ice (known as a ‘bergy bit’) about one-story high floats in the waters of Kongsfjorden in Svalbard on Tuesday, Sept. 6, 2016. This was two days after what was likely the largest calving event ever monitored from the Kongsbreen glacier front up until that point. (Photo: © Tom Yulsman)

Even if we somehow stopped climate change dead in its tracks right now, recent research shows that more than a third of the world’s 200,000 glaciers would melt anyway.

That’s because glacial ice takes decades to fully respond to the human-caused global warming that has already occurred. And as the inevitable thawing continues, meltwater flowing into the oceans will contribute to sea level rise, posing challenges for low-lying coastal cities already struggling to cope with flooding.

“Whatever we do, we have little wiggle room left because we have already committed to melting a large fraction of the ice,” says University of Bremen climate scientist Ben Marzeion, lead author on the study, which was published in the journal Nature Climate Change. I spoke with him at the Arctic Frontiers conference in Tromsø, Norway last week.

Findings like these can make us feel helpless, because they suggest we have little influence on the course of climate change. But there’s also a flip side to Marzeion’s research, one that offers an antidote to helplessness: In addition to documenting the inevitability of glacier melting, his findings also show just how much of a difference each one of us can make in saving glacial ice. 

For his research, Marzeion used climate models to feed information on temperature and other climatic factors into other models that predict how glaciers will respond. In particular, he and his colleagues focused on the kind of glaciers found in mountainous regions like the Alps, or in Norway’s Svalbard archipelago, leaving Greenland and Antarctica’s giant ice sheets out of the analysis. 

Many of Earth's glaciers are doomed

Hikers descend Longyearbreen, a glacier in Svalbard. The Arctic archipelago’s glaciers, which cover 60 percent of the land surface, have been thinning as the climate has warmed. Research shows that over the past 40 years, Svalbard has lost a volume of glacial ice equal to about 388 cubic kilometers. That works out to a cube nearly 100 miles on a side. [Photo: ©Tom Yulsman. Glacier data: Christopher Nuth et al, Svalbard glacier elevation changes and contribution to sea level rise, Journal of Geophysical Research: Earth Surface, Journal of Geophysical Research , 115 (f1) ]

It’s not that melting of ice in Greenland and Antarctica are unimportant. In fact, research published last week shows that Greenland’s ice is melting faster than previously thought and will likely trigger faster sea level rise in coming decades. 

But big ice sheets and the smaller glaciers of the kind included in Marzeion’s study are different beasts. And better understanding of how the latter are responding to human-caused warming is vital. That’s because their melting is already contributing about half of the 3 millimeters per year of global sea level rise currently being observed. That works out to about 0.05 inches annually. By comparison, Greenland has lately been contributing about 0.03 inches to sea level each year. 

In one of a number of modeling scenarios Marzeion and his colleagues undertook, they examined what would happen if we somehow kept the climate as it is now — a little less than 1 degree C warmer than it was in preindustrial times. 

In this scenario, “you keep exposing the glaciers to our current climate,” Marzeion said. And the question is, “How are they going to respond in the long term?”

In our conversation at the Arctic Frontiers conference, he summarized the results this way: “On a global scale, with the present day climate, roughly one third of the glacier mass will be lost. So there is a disequilibrium between what the glaciers are looking like at the moment, and what the climate is looking like at the moment.”

In other words, the glaciers take time to respond — they haven’t yet caught up to the climate warming we’ve caused so far. 

Turning off climate change overnight is obviously a physical impossibility. But we can work to limit future temperature increases by reducing how much heat-trapping carbon dioxide we’re pouring into the atmosphere. Read More

Frightening new visualization shows the deadly Camp Fire racing out of the mountains and enveloping Paradise

By Tom Yulsman | January 12, 2019 3:05 pm
The sophisticated modeling behind the visualization may provide better tools for getting people out of the way of wildfires

This animation of the Camp Fire is one of the tools used by scientists at the National Center for Atmospheric Research to study factors that made the wildfire so deadly.

Driven forward at breakneck speed by bone-dry winds, California’s Camp Fire blazed down out of the hills so quickly that the town of Paradise never really stood a chance.

In the animation above, you can get a good sense of how those winds blew the fire across Paradise and other towns. Scientist Janice Coen and her colleagues at the National Center for Atmospheric Research are using it to study the factors that made the rampaging blaze so deadly. It may also help point toward better tools for enabling emergency managers to get people out of the way of chaotic, fast-moving blazes.

The Camp Fire shows how badly such tools are needed. It killed 86 people, which makes it the seventh deadliest wildfire in U.S. history, and the 14th deadliest worldwide. The fire also incinerated 14,500 residential and commercial buildings, making it the most destructive wildfire in California history.

The animation was produced using a system that combines modeling of wildfire behavior with numerical weather prediction modeling. In addition to portraying the spread and intensity of the fire, the simulation depicts the wind field. The arrows show which way winds were blowing; their length and color correspond to speed. (Check out the bottom of the two keys at upper right for the color coding that corresponds to wind speeds.)

As the simulation progresses, the colors help us visualize gusts blowing over the landscape — which are themselves influenced by the wildfire itself. Look for wave-like patterns depicted in orange and red before the fire gets going. These are wind gusts. Once the fire begins, some of those gusts — the ones represented by the darkest reds — reach speeds of 40 meters per second. That’s almost 90 miles per hour! Read More

CATEGORIZED UNDER: Drought, select, Top Posts, Wildfire

Research showing steeper increases in ocean heat is not exactly new. So what’s up with all those headlines?

By Tom Yulsman | January 11, 2019 7:52 pm

There’s been good evidence that the oceans were heating up faster than thought. Now, scientists have fitted the puzzle pieces together.

The trend in the amount of ocean heat is shown for the period 1993 to 2015. Yellow, orange and red tones show locations where ocean heat has increased. (Source: Cheng, Lijing & NCAR. Last modified 10 May 2017. "The Climate Data Guide: Ocean temperature analysis and heat content estimate from Institute of Atmospheric Physics." Retrieved from

The trend in the amount of heat in the oceans is shown for the period 1993 to 2015. Yellow, orange and red tones show locations where ocean heat has increased. (Source: Lijing Cheng & NCAR. Retrieved from

So this morning, as I’m drinking my coffee and perusing news headlines, I see this in the New York Times: “Ocean Warming Is Accelerating Faster Than Thought, New Research Finds.”

The story was about a new paper published Thursday in the journal Science titled, “How fast are the oceans warming?”

This is a big deal, because human-caused global warming doesn’t affect just the land surface. In fact, more than 90 percent of global warming’s heat is absorbed in the oceans. That has helped prevent much steeper increases in temperature on land.

But all that heat going into the oceans isn’t really a benign phenomenon. By causing ocean waters to expand, it contributes to sea level rise. The heat also can make storms more destructive, and it’s putting enormous stress on ocean ecosystems — which we depend on heavily for food.

And in the long run, what goes into the oceans doesn’t all stay in the oceans. Heat eventually comes out of the water to contribute to warming atmospheric temperatures around the globe.

So knowing exactly how much heat is going in is very important. With that in mind, I checked out other stories about the new paper in Science, and I saw that many featured similar headlines as the N.Y. Times.

More about the scientific paper in a minute. But first, I have to say that I realized I had seen very similar headlines before. Just this past October, for example, I saw this in Scientific American: “The Oceans Are Heating Up Faster Than Expected.” According to the story, a “new study published yesterday in the journal Nature concluded that the global oceans may be absorbing up to 60 percent more heat since the 1990s than older estimates had found.” Read More

We’ve been waiting for El Niño, but all we’ve got is El Limbo

By Tom Yulsman | January 10, 2019 7:38 pm

The animation above shows how sea surface temperatures in the Pacific Ocean varied from average week by week, starting in February 2018 and continuing through the first week of January 2019. At the start, cooler than normal temperatures prevail along the equator. As it continues, the surface waters warm, as indicated by the change from blue to red colors. 

The Pacific Ocean along the equator is practically shouting to the atmosphere, “Hey, we got an El Niño goin’ on over here, what’s your problem?” But the atmosphere just doesn’t seem to want to listen.

Bottom line: We’re still waiting for El Niño.

The climatic phenomenon is significant because it can influence weather around the globe, favoring some damaging impacts but also some welcome ones too. For example, during El Niño winters, an extended, more powerful jet stream tends to steer storms into the southern half of California and across parts of the U.S. Southwest.

That extra moisture sure would be nice right about now. That’s because the Four Corners region, where Arizona, New Mexico, Colorado and Utah all come together, is suffering from a horrible, persistent drought. But unfortunately, no dice — or, more precisely, no rain and snow — at least for now.

Here’s the deal: Read More

My pick for the most compelling — and scary — remote sensing image of 2018

By Tom Yulsman | December 29, 2018 6:23 pm
The top remote sensing image of 2018

An image of California’s Camp Fire, created using natural color and infra-red data acquired by the Landsat-8 satellite on Nov. 8, 2018. (Image courtesy Pierre Markuse)

This past year brought all too many disasters, including rampaging wildfires, destructive volcanic eruptions, swirling tropical cyclones, and a host of other events that brought misery to millions of people worldwide.

Many were visualized by satellites looking down on Earth, and as 2018 draws to a close, I thought I’d feature one that I found to be particularly compelling. It’s the image above showing California’s Camp Fire, created by blogger and remote sensing expert Pierre Markuse. It’s my personal pick for top remote sensing image of 2018.

The Camp Fire ignited on Nov. 8, 2018 and quickly exploded, engulfing and ultimately destroying the town of Paradise, California. As of Dec. 19, the death toll stood at 86 people, which makes it the seventh deadliest wildfire in U.S. history, and the 14th deadliest worldwide. (Jeff Masters of the Category 6 blog tallied the statistics here. But keep in mind that since he wrote his story, the death toll of the Camp Fire was actually reduced.)

Ultimately engulfing 153,336 acres — about half the size of the City of Los Angeles — the Camp Fire was also the most destructive wildfire in California history, incinerating 14,500 residential and commercial buildings.

Markuse created the image using data from the Landsat-8 satellite. I find it particularly noteworthy for a number of reasons. First, you can see the town of Chico, population 93,293, toward the left, partly obscured by the huge smoke plume. This provides a sense of scale. Read More

This started as a story about really cool clouds on Earth, but then it led to this: Does it snow on Mars?

By Tom Yulsman | December 29, 2018 4:44 pm
Snow falling from clouds near Boulder, Colorado on Dec. 19, 2018 did not reach the ground — a classic example of virga. That got me to thinking: Does it snow on Mars?

Snow falling from clouds near Boulder, Colorado on Dec. 19, 2018 did not reach the ground — a classic example of virga. (Photo: ©Tom Yulsman)

Mars is certainly cold. With temperatures that can plunge to more than negative 100 degrees Celsius, it’s bloody frigid!

But as cold as it might get, does it snow on Mars?

This wasn’t the first thing that came to mind when I photographed the scene above near Boulder, Colorado with my iPhone. But when I got home and started investigating the beautiful phenomenon I had documented, I eventually came around to that rather un-obvious question. How I came to it — as well as the answer — is a bit of an interesting journey, so I hope you’ll keep reading.

First, what about those clouds in the image above? If you live somewhere with wide open vistas, you’ve probably seen the phenomenon yourself: darkish streaks appearing to hang from a cloud deck.

This is called “virga” —  precipitation falling from the clouds but mostly not reaching the ground. I’ve seen virga many times before, but usually in summer. This is when temperatures are high and humidity near the surface can be relatively low, causing shafts of rain falling from clouds to evaporate before the drops reach the ground.

But I shot the photo above on December 19th, two days before the winter solstice and well into meteorological winter. At the elevation of the cloud deck, temperatures were almost certainly well below freezing. So the virga probably consisted of little ice crystals. As they fell toward the ground, they simply sublimated — meaning they went from the frozen state to water vapor without first condensing into liquid.

I decided to write a post about it here at ImaGeo, and as I did my research, my mind wandered far from Colorado. All the way to Mars, which I knew had its own clouds.

I began wondering whether Martian clouds feature ice crystals streaming downward to form virga. Do ice crystals actually reach the ground as snow? And what might all of this look like from the surface? Read More



ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

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