Weather: Freezing rain or sleet

[AuntPeggy]

As we were driving out to the airport and watching the stuff sliding around on the windshield and scooted aside by the wipers, Hubby and I tried to decide whether the airborne slush was freezing rain or sleet. Mainly because neither of us really knows the definition or difference.

What is freezing rain? What is sleet? What are the differences?

 

[steingar]

Freezing rain is liquid when it hits your car, but promptly freezes up. Sleet partially freezes on the way down. Drove through both on Saturday, and both suck. We're too far North to see much of those things, we mostly get snow. Lots of that this year.

 

[Dr. O]

Flew Saturday in the Great Lakes ice machine... 2000 foot ceiling and no visible precip... Out over Lake Huron to look at the ice fishermen out there 8-10 miles offshore... Went through some light haze and picked up ram air icing on the windscreen and leading edges... Had to lean way to the left to have a view of the runway on landing by peering out the side window - yes defrosters on, but not effective in continued impact icing... That landing was so much fun I did a T&G and did it a second time... Typical winter flying around the lakes...

denny-o

 

[AuntPeggy]

Freezing rain is liquid when it hits your car, but promptly freezes up. Sleet partially freezes on the way down. Drove through both on Saturday, and both suck. We're too far North to see much of those things, we mostly get snow. Lots of that this year.

So, airborne slush is sleet.

 

[Ted]

Seems like a Scott D. question to me, but from my experience...

Freezing rain is liquid that is below freezing but not yet frozen solid. When it hits your plane, it freezes (under certain conditions, anyway). This is what we call clear ice, and generally referred to as a very bad thing. I've driven through freezing rain a lot, and I've never seen it stick to my car the same way it sticks to my plane.

Sleet is the same SLD (supercooled liquid drops) that have been frozen, so it's ice pellets. It shouldn't stick to your car or plane, because it's already frozen.

To tell the difference in your car, open your window and stick your hand out. If it's sleet, it will hurt. If it's freezing rain, it will just be cold.

 

[gprellwitz]

[FONT=Arial, Helvetica, sans-serif][SIZE=+2]Freezing Rain: [/SIZE][/FONT]Rain that falls through a shallow layer of freezing temperatures at the surface and freezes upon impact to form a coating of glaze upon the ground and on exposed objects (e.g., pine trees).

and

[FONT=Arial, Helvetica, sans-serif][SIZE=+2]Sleet[/SIZE][/FONT]: Generally transparent, globular, solid grains of ice which have formed from the freezing of raindrops or the refreezing of largely melted snowflakes when falling through a below-freezing layer of air near the earth's surface. (Glossary of Meteorology)

so it seems like what others have already said.

 

[AuntPeggy]

Sounds like we were experiencing yet another permutation, half snow, half melted snow (rain).

 

[rottydaddy]

Sleet is somewhat of a slang term for ice pellets. We see that in a surface observation or terminal forecast as PL (this was changed from PE since rain and ice pellets falling at the same time might get coded as RAPE).

Ice pellets (sleet) are unmistakable. It resembles small hail, but is not produced by the same process as hail. When it hits an object such as a car windshied, it will bounce off. It is formed when snow falls through a shallow melting layer (temperature slightly above 0°C). This converts the snow to a rain drop with a nucleus that still has some crystalline structure (not completely melted). When this pseudo-drop falls through a subfreezing layer below it will refreeze into a hard nugget we call an ice pellet.

Doesn't "sleet" refer to ice pellets mixed with rain and/or snow(I like Peggy's "airborne slush" analogy; that seems to fit)?
I've seen "dry" pellets... in fact, a little over 10 years ago there was a storm like that near me that left inches of the damn things on the ground, as if a giant Sno-Cone had been dumped on the city. Mini-hail, very fine, coming down by the dumpster-full... the actual number per unit of volume was probably about the same as raindrops in a torrential downpour. People were running for shelter, because they hurt!! But no rain or snow, just the pellets.

 

[EdFred]

I just report it as UP and stay in the house.

 

[AuntPeggy]

Sleet is somewhat of a colloquial term for ice pellets. We see that in a surface observation or terminal forecast as PL (this was changed from PE since rain and ice pellets falling at the same time might get coded as RAPE).

Ice pellets (sleet) are unmistakable. It resembles small hail, but is not produced by the same process as hail. When it hits an object such as a car windshied, it will bounce off. It is formed when snow falls through a shallow melting layer (temperature slightly above 0°C). This converts the snow to a rain drop with a nucleus that still has some crystalline structure (not completely melted). When this pseudo-drop falls through a subfreezing layer below it will refreeze into a hard nugget we call an ice pellet.

Freezing rain, on the other hand, comes in two flavors. The first is produced from the same process as described above, except, the melting layer is typically deeper or warmer. This completely melts the snow. This is called classic freezing rain as I describe in my latest member workshop. The other flavor of freezing rain can have a similar profile, except, that the process doesn't start out as snow...it's an all-liquid process as I discuss in this IFR magazine article.

What you potentially experienced based on your description is wet snow. That is snow that has nearly melted, but not quite. Keep in mind that ice pellets, rain, freezing rain and snow can all occur together in the atmosphere. So, the presence of PL is indicative of SLD aloft.

Hope this helps.

Thanks.