Graupel Storm (March 30, 2008)

[pendletonboy]

Graupel is precipitation that forms when supercooled droplets of water condense on a snowflake, forming a 25 mm ball of rime; the snowflake acts as a nucleus of condensation in this process.

[pendletonboy]

The white round fluffy stuff is Graupel. Also, frozen balls of ice, in the winter-time is referred to as sleet. However, frozen ice balls in the summer is referred to as hail. Although they look similar, what they are referred to only depends on the time of year it occurs. Hence, hail in the late spring and summer and sleet in the late fall and winter. Graupel, sleet and hail are actually quite common here in Northeastern Oregon.

[amazonhippie]

@pendletonboy

What?!!!

Graupel, Hail, & Sleet are NOT the same.

GRAUPEL is rime on a snowflake. Rime is fog that freezes on snowflakes. Graupel is 2 - 5 mm... not 25mm.

SLEET is fast falling rain that freezes on the way down.

HAIL is water droplets that either...

A - fall very slowly collecting more as they go. OR...

B - ride an elevator of drafts, rising & falling as they grow, until they are too heavy for the upward draft.

[pendletonboy]

@amazonhippie

Read a little more careful.....I never said they were all the same. I described each, individually. 25mm WAS a typo....should have been 2-5mm. Definition given by Wikipedia:

Under some atmospheric conditions, snow crystals may encounter supercooled cloud droplets. These droplets, which have a diameter of about 10 µm, can exist in the liquid state at temperatures as low as −40 °, far below the normal freezing point.

[pendletonboy]

Contact between a snow crystal and the supercooled droplets results in freezing of the liquid droplets onto the surface of the crystal. This process of crystal growth is known as accretion. Crystals that exhibit frozen droplets on their surfaces are referred to as rimed. When this process continues so that the shape of the original snow crystal is no longer identifiable, the resulting crystal is referred to as graupel

[pendletonboy]

Graupel was formerly referred to by meteorologists as soft hail. However, graupel is easily distinguishable from hail in both the shape and strength of the pellet and the circumstances in which it falls. Ice from hail is formed in hard, relatively uniform layers and usually falls only during severe thunderstorms

[pendletonboy]

Graupel forms fragile, oblong shapes and falls in place of typical snowflakes in wintry mix situations, often in concert with sleet. Graupel is also fragile enough that it will typically fall apart when touched.

[actioman2006]

This is not graupel, it's hail!

Watch my video response and you will see graupel

[supercell1995]

i watched the weather that day, and they said it was hail, there were thunderstorms in the area that produced hail, and even a funnel cloud was reported near a farm. you probably didn't hear any thunder because the storm in this video didn't contain that much convection, or almost no convection at all

[mallomon]

That's hail (unless you're from Germany, in which case they do call it Graupel over there). I recognize that flag (and the date)... are you from the Pacific Northwest... like Portland?

[mallomon]

I retract my former statement. :P

I believe there's a whole class of precipitation that's not well-described. Graupel is rimed snow, and this is definitely not that. However, the softness of the pellets and the speed at which they fall is definitely more similar to graupel than to either hail or snow.

I would now contend that this is somewhere between pure snow and pure hail. A snowflake partially melts, then is lifted back up to a subfreezing layer. It's like hail but with snow as the nucleus

[richarddx22]

You might actually mean "graupel".

[W7ENK]

Yes, you're probably right.  I've never seen this word written, only heard it said by meteorologists on the television, so I just took my best stab at spelling it.

Thanks for the correction!