Parts of Pennsylvania and New Jersey saw giant icicles form in mid-February.

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Montgomery County on Saturday, February 20.  Credit: Christine.

They formed on gutters and around doorways.

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Bethlehem on Saturday, February 20.  Credit: Bryan Zehner

 

Then, they started melting and falling off, despite the weather being only a few degrees above freezing.  

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It goes to show you the power of the sun beating down on them.

Ice Berks County

Berks County on Saturday, February 20.  Credit: John Kupetz

It's a lot like your car in the summer: it's always much warmer inside it than outside it on a hot day.  That's because the sun beats down on the car, warming the inside of it. All that warmed up air gets trapped inside the car.

As for icicles, you'll see water drops drip off of them as they melt.

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Taken near Bethlehem on Saturday, February 20.  Credit: Marty McGurie.

The water drops will be round.

Those circular drops are actually what a raindrop looks like.   You'll often hear that raindrops are tear shaped, but that's not true.

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Taken near Bethlehem on Saturday, February 20.  Credit: Marty McGurie.

Raindrops are usually spheres.  

But, if a raindrop is big and if it falls through a lot of air, it will start looking like the top half of a burger bun.  That's because air pushes up on the bottom of the round raindrop as it falls, flattening out the bottom. 

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Raindrops on a sunroof window.

A bunch of tiny circular water drops floating in the air make up fog.  Fog is just a cloud near or at the ground.

In the winter, we'll sometimes see fog on cold mornings.  This happened last Sunday.

Sunday 2/14 fog

A foggy Valentine's Day morning.

When fog is down at the ground and temperatures are below freezing, you'll have freezing fog.

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There's fog around frosty cars.  The air temperature was 27 that morning, so that fog was freezing fog.  The water drops in the fog would freeze when they hit something cold, like a car.

This means the tiny, circular water drops making up the fog instantly freeze when they hit something.  If they hit something with frost or snow on it, they'll make a textured ice, called rime. 

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The side mirror has frost on it.  As this car drove through freezing fog, the water drops in the fog froze onto the frost, making textured ice.

In this picture from Mount Washington, New Hampshire, the guys having some fun in alien costumes are pointing out the textured snow caused by the fog, which you see in the background, freezing on contact with the snow on the sign.

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New Hampshire.  Credit: Meteorologist Caleb Meute

When the water drops in freezing fog hit something cold that doesn't have snow or ice on it, they freeze into ice.

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As this car drove through freezing fog, the water drops in the fog instantly turned to ice when they hit the radio antenna and other parts of the car.

Last Sunday, the freezing fog didn't make it all the way down to the ground.  It stayed up in the sky, just above the ground.

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WFMZ studios on Valentine's Day morning.

This lead to the air at the ground being pretty humid despite temperatures below freezing.

As that humid air ran into tree branches, the moisture in the air instantly turned into tiny pieces of ice.  Going from the gas form of water to the solid form creates a special kind of frost that looks fuzzy.

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Lehigh County on Sunday, February 14.  Credit: Karen Snyder.

As more humid air hits this frost, this frost will grow outward, looking even fuzzier.