Archive for the 'Weather & Sky' Category

Apr 01 2015

Corals Tell The Climate Story, April 16

Coral reef at Palmyra Atoll (photo by Jim Maragos/U.S. Fish and Wildlife Service)

Coral reef at Palmyra Atoll (photo by Jim Maragos/U.S. Fish and Wildlife Service)

Knowing the Earth’s past climate is key to understanding the future but our records of the past are sketchy.  Paleoclimatologists turn to fossils for help.  In cold and temperate areas they analyze ice cores and ancient tree rings.  In the tropics corals tell the climate’s tale.

Obtaining a record of the warm oceans’ history is important because so much of Earth’s weather is controlled by conditions in the Tropics.  Think El Niño and La Niña, for starters.

In the tropical Pacific Dr. Kim Cobb examines live and fossil corals to assemble a climate record that now spans 7,000+ years.  Thanks to the University Honors College she’s coming to Pittsburgh on April 16.  Through video and photos, she’ll take the audience to her field sites to hear the corals tell their climate story.

Dr. Kim Cobb
Corals as Climate Communicators
April 16, 2015, 4:00 PM

Charity Randall Theatre (in the Stephen Foster Memorial Building)
4301 Forbes Ave

Here’s a quick video of Kim Cobb discussing climatology.  She describes herself on  Twitter as “40% Climate Scientist, 40% Mom and 20% Indian Jones.”  Her lecture on corals will not be a dry subject!


This lecture is free and open to the public but space is limited. Click here to read more about this University of Pittsburgh Honors College event and reserve your seat.


(photo of coral reef at Palmyra Atoll (a location where Kim Cobb works on corals) by Jim Maragos/U.S. Fish and Wildlife Service via Wikimedia Commons. Video of Dr. Kim Cobb via

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Mar 31 2015

More Deer, Less Moose

Moose and deer (both photos from Wikimedia Commons)

What happens when the interval between spring thaw and leaf out gets longer?  Fifty years of detailed observations in New Hampshire’s Hubbard Brook Experimental Forest tell the tale.

In New Hampshire, where snow covers the ground all winter, spring thaw is a welcome event that finally exposes the soil.  Weeks later after lots of warm air and sunshine the trees leaf out.  In between these two events the sun warms the soil, the plants emerge, and wildflowers bloom.

Hubbard Brook Experimental Forest has kept detailed records of temperature, precipitation, snowpack, plants, animals, birds and invertebrates for more than half a century. An analysis of the data, published in BioScience in 2012, showed that the forest is getting warmer and wetter and the interval between spring thaw and leaf out has increased by 8 days.  Climate change is separating spring’s above ground (air) responses from the soil responses.

In the post-thaw interval severe cold events freeze the exposed soil and kill plant buds and invertebrates. This threatens some deciduous trees (yellow birch and sugar maple in New Hampshire) and birds find fewer invertebrates when they return from migration.  The record shows the mix of plants and animals is changing.

There are even changes in large animals.  For the past 50 years the snowpack has declined, an outcome that favors deer over moose and that seems to be happening at Hubbard Brook.

More deer, less moose.  If you write it down now you can see the trend later.

Read more here in Science Daily, December 2012.


p.s. It should be “More Deer, Fewer Moose” but I am quoting one of the articles and happen to like the ungrammatical juxtaposition.

(photo of moose by Ronald L. Bell, USFWS via Wikimedia Commons.  Photo of deer by josephamaker2018 via Wikimedia Commons. Click these links to see the original images.)

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Mar 21 2015


Published by under Weather & Sky

Analemma photo taken 1998-99 ourside Bell Labs in NJ by Jack Fishburn (GNU free licensing, Wikipedia)

The word Analemma sounds like a girl’s name or perhaps an exotic fruit but in fact it’s the name for that figure 8 hanging in the sky above.  You won’t see it in Nature but you may have seen it as a symbol printed on an old-fashioned globe of the world.

Technically speaking an analemma is the location of one celestial body as viewed from another for one complete orbit.  Practically speaking it’s the Sun’s position throughout the year at the same location and time of day on Earth.   I was surprised to learn it’s a figure 8 but that’s because the Earth’s orbit is elliptical and tilted.

This photo took a whole year to create.  Every other week in 1998-1999, Jack Fishburn took a photograph of the sun’s position from his office window at Bell Labs.  He was careful to place the camera in the exact same position and snap the photo at the same time of day (correcting back to Standard Time during Daylight Savings).  After collecting a year of photographs he overlaid them to create the analemma.

Tunc Tezel did the same thing at Baku, Azerbaijan and made it a movie here.

You can create your own analemma if you’re persistent (one whole year) and precise (same camera location and time of day for every photo) and have access to Photoshop.

When you’re done you’ll know that the top of the 8 is the summer (northern) solstice, the bottom is the winter (southern) solstice, and the crossover point is both equinoxes.  Today, one day after the Northern Equinox, the sun is very near the center of the analemma.


(photo by Jack Fishburn via Wikipedia GNU Free License. Click on the image to see the original)

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Mar 02 2015

Heads Up!

Published by under Weather & Sky

Icy sidewalk,2 Mar 2015 (photo by Kate St. John)

Mountains in Alaska?  No, my icy sidewalk.

Yesterday more than three inches of wet snow fell across Pittsburgh.  Sometimes it changed to rain.  Overnight it froze.

Expecting dangerous footing, I put on my ice cleats and went out to see.

Stabilicer ice cleats (photo by Kate St. John)


Under light snow on the sidewalk … Viola, a glacier!

Icy sidewalk, 2 Mar 2015 (photo by Kate St. John

That’s not all.  Last night I noticed that my car, parked on the street, was standing in three inches of water because ice dams prevented the water from draining.  In the dark I heaved snow and water to the storm drain, hoping to prevent my tires from being locked in ice this morning.  What do you think? Am I stuck?

Tire in ice (photo by Kate St. John)

I spread salt and came indoors, feeling a little smug that my ice cleats worked so well.

But the ice has one more trick up its sleeve.

Warning sign, Montreal, falling snow and ice (photo from Wikimedia Commons)

Heads up!


(all photos by Kate St. John, except the ice warning sign in Montreal is by Paul Joseph via Wikimedia Commons. Click on the sign to see its original)

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Feb 26 2015

Ice Jam Season

Published by under Weather & Sky

Ice and gulls on the Monongahela River, 25 Feb 2015 (photo by Kate St. John)

Yesterday morning the river at Duck Hollow was so icy that the gulls could walk across it.

With temperatures as much as 33 degrees below normal, western Pennsylvania is swamped in ice and long overdue for a warm spell.  When the weather breaks, so will the ice.

In some places we’ve already seen some flooding.  On Tuesday February 24 The Weather Channel wrote:

In western Pennsylvania, flood warnings have been issued for Armstrong and Clarion counties due to an ice jam that is blocking the Allegheny River, creating a backflow of water into Parker, according to an AP report. The warning is in effect until 7 a.m. Thursday. State Route 268 has been flooded and at least two people have been rescued from the floodwaters in Parker.

In February 2009 I was hiking at Raccoon Creek Wildflower Reserve when the ice broke and jammed in front of me.  Click here or on the gray-brown ice photo for my in-person (Throw Back Thursday) report.

Ice jam on Raccoon Creek (photo by Kate St. John)


(photos by Kate St. John: Ice and gulls on the Monongahela River at Duck Hollow, 25 Feb 2015.  Ice on Raccoon Creek, 8 Feb 2009)

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Feb 20 2015


Published by under Weather & Sky

Most of us were asleep at 4:50am on Tuesday morning when a 500-pound space rock hurtled into Earth’s atmosphere.  It was on its way to Pittsburgh.

Fortunately the meteor’s aim was off a bit — just enough to miss all the populated areas and disintegrate east of Kittanning.

Considering its early morning arrival we wouldn’t know about it if a few people hadn’t been awake.  Eyewitnesses reported seeing and hearing it on the American Meteor Society (AMS) website and NASA’s camera at Allegheny Observatory recorded its arrival in the video above.

Using eyewitness reports AMS generated a map of its trajectory.  Scroll down to see what it was aiming for.  Yikes!

We were lucky.  In an uncanny space-time coincidence a very big meteor whooshed over Russia two years and two days before the Kittanning event.  It weighed 10,000 tons(*) and injured over 1,000 people.  February 15, 2013 in Russia.  February 17, 2015 in Pittsburgh.

…What is it about February?

I wish I had seen it.  I was awake but I wasn’t paying attention.


(YouTube video of the February 17 fireball from NASA’s Marshall Center)

(*) that’s 40,000 times heavier than the meteor at Kittanning.

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Feb 07 2015

Flying Saucer?

Published by under Weather & Sky

Lenticular cloud in Hawaii (photo from NASA via Wikimedia Commons)

Whoa!   Is this a flying saucer?

No, it’s a lenticular cloud over Mauna Kea, Hawaii.  This was the Astronomy Picture Of the Day on August 21, 2005.

Click on the image to read more about it.


(photo from Wikimedia Commons. Click on the image to see the original)

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Jan 21 2015

Io! Did You Know… ?

Published by under Weather & Sky

Screenshot of Io video from

Continuing my Jovian January theme …

Yo! Did you know that Jupiter’s moon Io is the most volcanically active world in the solar system?

Io is the size of our Moon but a very inhospitable place.  It’s covered in sulfur which makes pretty shades of yellow but unbreathable air.

To make matters worse, Io is so small and Jupiter is so large that Jupiter’s gravity causes 100 meter land-tides on Io’s surface.  Yes, the land rises and falls 330 feet as Io orbits Jupiter.  No wonder Io has more than 400 active volcanoes!

In 2007 NASA’s New Horizons spacecraft took photos of a plume coming off the top of Io.  What was it?  A volcanic eruption rising 300 miles above Io’s surface!

Click on the screenshot above (or click here) to see a video of Io in action.

Yo, Io!


(video linked from

p.s. Scientists to Io: “Your volcanoes are in the wrong spot.”

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Jan 20 2015

Warmest Year Ever…

Published by under Weather & Sky

Land & Ocean Temperature Departure From Normal, 2014 (image from NOAA's National Climate Data Center)


Last week NOAA’s National Climate Data Center reported that 2014 was the warmest year ever recorded on earth.  Yes, there were undoubtedly warmer years before humans were around and perhaps some warm years before we bothered to write it down but for this century and in our lifetimes, it was hot.

Even after the coldest winter the east-central U.S. can remember, the average U.S. temperature was 0.5 degrees above normal.  (Ask Westerners how hot they were!)  Here’s a month-to-month video that shows that even the East was hot in December.

Climate scientists agree(*) that the warming is caused by humans and there will be sobering results.  We’ve caused it.  We record it.  We report on it.  But will the news change anything?

On a political and media level in the U.S. this news has generated interest and talk but no real action.  On the natural level — among the air, water, birds, plants, and animals that I care about — it is big news and they’re doing something about it.  The air is hotter, the ice is melting, the sea is rising, and the plants, animals and birds are moving north or uphill.

Humans are doing something too, even here in the U.S. where our society has not taken up the cause.

Humans are coping with droughts and building bigger dikes and seawalls.  We’re trying to prevent deaths from frequent heavy downpours.  We’re planting warm-season or drought-resistant flowers and crops.  We’re rewriting insurance policies to exclude disasters that are certain to happen. In some cases we’re already abandoning land that’s altered by flood or drought.

By the end of the century our world will look very different.  Right now the news is “hot.”

Read more here.


(map and video from NOAA’s National Climate Data Center)

(*) That number is “97% of scientists agree.”  Discussion of that number can be found here.  I am not going to discuss the number. Plenty of others have already done so.

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Jan 18 2015

Natural Ice Sculptures

Published by under Hiking,Weather & Sky

Icicles along the Butler-Freeport Trail near Monroe Road (photo by Kate St. John)

A week ago I found beautiful ice formations along the Butler-Freeport Trail at Monroe Road.

Water’s constant drip made a curling fountain.

And some of the icicles accumulated frosty teeth.

Frosty teeth on the icicles (photo by Kate St. John)


The weather was warming that day and part of this massive ice cliff …

Cliff lined with massive icicles (photo by Kate St. John)

… had crashed to the ground across the trail.

Icicles crashed to the ground (photo by Kate St. John)

Here’s one of the smaller chunks near my boot.  I’m glad I wasn’t there when it fell.  Watch out below!

Chunk of fallen icicle for size comparison (photo by Kate St. John)


This weekend the weather has been unseasonably warm.

I wonder what the icicles look like now.


(photos by Kate St. John — taken with my cellphone because I forgot to bring my camera)


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