name for snow driven into air by wind?

[forestgnome]

I've always called them 'snow clouds'. There must be a name for those clouds of snow that are whipped into the air by strong winds. It's a very powerful image of cold and danger. Picture below.

 

[NH_Mtn_Hiker]

Ummmm....how about blowing snow.

I don't think it quite qualifies as a snow squall.

 

[dms]

I think that it's called spindrift.

 

[Frodo]

In fluid mechanics it's called the "boundary layer", which happens when a fluid (air) creates friction while passing over a solid. In this case you can see the results of the wind's friction...

Nice picture!

 

[DougPaul]

Spindrift appears to be one name. I couldn't find a formal definition, but windblown snow seems to a a synonym.

There are also spindrift avalanches which occur during heavy snowstorms--the snow collects somewhere and periodically avalanches as a very light airy cloud. Annoying, but they don't usually knock a climber down. Wind not required.

If it is heavy, it would be a ground blizzard:
From http://www.personal.psu.edu/users/t/n/tnn107/Tiffanysblizzard.htm

"Ground Blizzard." Dr. Charles Hosler, professor emeritus of Meteorology here at Penn State, explains what a Ground Blizzard is: "A ground blizzard is basically a blizzard without snow. When skies are clear and no snow is falling, but winds are high enough to blow snow already on the ground fast enough to reduce visibility to less than a quarter mile, you have a ground blizzard. These happen in Antarctica almost everyday. A ground blizzard is like a dust storm, only with snow."

I have been in a very shallow ground blizzard on Boot Spur--we couldn't see our feet and horizontal visibility was somewhat limited. The sky above was blue.

However, the picture looks like a lenticular cloud to me. In this case, a thin humid layer which condenses as it goes over a high spot. It doesn't look attached to the mountain to me.

Useless factoid: the wind driven snow plume off Mt Everest can be over 100 mi long.

Doug

 

[forestgnome]

Thanks for responses. Doug, thanks for researching; I came up with that also, but nothing for a cloud of snow lifted off of the ground by wind.

It does look like a lenticular, but I don't think so because I sat and watched this from the road at Pinkham Notch before climbing Boott Spur on Saturday. It would only last for 10 or 20 seconds, then dissappear, then appear and disappear again. It was extremely gusty up above treeline. Then again, don't know if that would eliminate lenticulars.

Until I learn of a recognized meteorological term, I'm going to call them 'snow devils', relating them to dust devils.

Happy Trails!

 

[Jay H]

I've always called it spindrift myself. Lenticulars, from my understanding is moisture that forms by winds on high mountains, etc. moisture that is from the air, but actual snow that is blown off the peaks from the wind is spindrift...

I could always be wrong of course, I'm not a meterologist!

Jay

 

[Mark]

If it is heavy, it would be a ground blizzard:
From http://www.personal.psu.edu/users/t/n/tnn107/Tiffanysblizzard.htm...

Growing up outside of Buffalo, we would occasionally get ground blizzards. If there was a big snowfall after Lake Erie froze over and strong winds came in off the lake, the snow on the ice would get blown onto land. You'd get a blizzard with the sun shining. I remember getting caught in a complete white out once during a ground blizzard. I couldn't see anything around me, but overhead there were bright blue skies.

 

[DougPaul]

It does look like a lenticular, but I don't think so because I sat and watched this from the road at Pinkham Notch before climbing Boott Spur on Saturday. It would only last for 10 or 20 seconds, then dissappear, then appear and disappear again. It was extremely gusty up above treeline. Then again, don't know if that would eliminate lenticulars.

This dynamic sounds more like windblown snow. Kind of hard to see dynamics in a still photo... But, IMO you are correct, there could be "bubbles" of humid air which form short lived lenticulars.

Until I learn of a recognized meteorological term, I'm going to call them 'snow devils', relating them to dust devils.

IIRC, I've only seen the term spindrift in the mountaineering literature. (I'm not a meteorologist, so my reading might be biased...)

IMO, snow devil would be misleading--to me it implies a vortex (miniature tornado). Spindrift is just wind or gravity (in the case of a spindrift avalanche) driven snow. I would use the term spindrift. If it blows off the mountain into its own "cloud", then snow plume would be appropriate.

Doug

 

[DougPaul]

Lenticulars, from my understanding is moisture that forms by winds on high mountains, etc. moisture that is from the air, but actual snow that is blown off the peaks from the wind is spindrift...

A lenticular is a specific kind of cloud. A humid layer of air is blown over a high spot (ridge or peak) and forms a cloud over/slightly downwind of the high spot because the air is forced upward and thus cooled. If you look carefully, you may be able to see it forming on the windward edge and evaporating on the leeward edge. They frequently look like cloud caps and can have multiple layers. In the case of a ridge, you can have several downwind lenticulars at the tops of each wave.

If the lenticulars are growing, it is a sign that the weather is deteriorating.

For a bunch of pics see http://www.crystalinks.com/lenticular.html

For lots more, try a google search on "lenticular cloud":
http://www.google.com/search?hl=en&q="lenticular+cloud"&btnG=Google+Search

Doug

 

[forestgnome]

OK, spindrift it is, at least in conversation with others. I'll call them snow devils to myself because I have my own names for many things out there, such as 'storm maker' (Mt. Washington) and 'mountain dove' (gray jay). I talk to myself alot, I hike solo.

Thanks, all. I picked up a cloud fieldguide today, very interesting.

Happy Trails!

 

[w7xman]

Actually...

I've always called them 'snow clouds'. There must be a name for those clouds of snow that are whipped into the air by strong winds. It's a very powerful image of cold and danger. Picture below.

Hey forestnome...

Those are actually a formation of orographic stratocumulus. Not blowing snow at all, though from afar it looks like blowing snow or spindrift. Similar to this pic (3rd down) from the MWO photojournal. http://www.mountwashington.org/photojournal/2000/07.html

The crew at the summit the other day got some pics of them as well, presumably from the same time you did. I'll post them in a few.

Really great shot.

 

[w7xman]

Hey forestnome...



The crew at the summit the other day got some pics of them as well, presumably from the same time you did. I'll post them in a few.

Through the window, but also taken on the 8th...

http://www.mountwashington.org/comments/2006/ALLAKESTQ.jpg

This wispy 'lenticulars' = orographic stratocumulus

 

[forestgnome]

Thanks, w7xman! Orographic stratocumulus.....great name, I love clouds.

They must have been appearing due to conditions, but then dissappearing due the the gusts(not being formed by gusts). Actually, this makes sense because it was gusty when I made it above treeline, but no orographics.

Thanks for the info!

Happy Trails!

 

[Artex]

Oh, cool! I wondered what they were called. Thanks for starting this thread.

Here's a few pictures of said phenomenon on Mt. Katahdin that I took last summer:

Clouds One

Clouds Two

Clouds Three

 

[Head]

Nice pics all! Funky pic #3 Jamie...looks like a buncha mini tornadoes forming....weird!

 

[DougPaul]

More on lenticular/orographic clouds:

From http://www.theairlinepilots.com/met/clouds.htm#Orographic Stratus

Orographic Stratus

* Distribution: Over hills and mountain ranges worldwide.

* Height: 0 to 1000 feet above ground level.

* Cause: Lifting of moist air mass by landform.

* Associated Weather: May produce fog, light drizzle or light snow showers.

* Hazard Warning: Can be an aviation hazard as it masks terrain.

Orographic clouds are formed when moist air, carried on a prevailing wind, is lifted by an elevated landform, such as a mountain range, to a level where condensation takes place. Among the most common orographic clouds is orographic stratus. This low-level formation occurs most frequently in areas, such as coastal regions, where the air flow is heavily moisture laden. Generally, the landform must be at least 500 feet high to generate cloud, and higher in areas of clean, dry air, such as deserts.

Unlike normal stratus, which is carried about by the external wind field, orographic stratus tends to remain stationary. The wind flows through the area of condensation, constantly regenerating cloud as the air rises and dissipating it as the air descends on the other side of the landform.

The extent of this type of cloud depends on the humidity of the surrounding air mass. If the air contains a high level of moisture, cloud can begin to form well down the windward slope of the landform, wrap around the peak, and extend some distance down the other side. A good example of this type of formation is the "tablecloth" that often drapes the top of Table Mountain near Cape Town in South Africa.

The extent of the cloud is also determined by the steepness and elevation of the landfornn, the strength of the wind, and the direction of the wind relative to the landform. Strong wind blowing at right angles to a steep mountain will create greater uplift and generate more cloud.

Since low-level moisture and high land are essential ingredients in the formation of orographic stratus, areas that have high humidity and steep terrain -- tropical islands such as Hawaii, for example -- are particularly conducive to the formation of these clouds.

Sometimes, there is insufficient moisture in the lower layers of the atmosphere to allow condensation at ground level, but with increasing altitude and lower temperatures, condensation may be possible. In this case, lifting of the air mass by a landform can produce middle-level orographic formations, known as lenticular clouds.

From http://www.lpl.arizona.edu/~rhill/alpo/marstuff/discrete.htm

In the Earth’s atmosphere clouds often form on the windward side of mountains and are classified as Orographic Clouds. Orographic clouds are clouds that develop in response to the forced lifting of air by the earth's topography, such as mountains, and fall into the following general categories:

Conjoined orographic clouds - covers entire mountain, forms on windward side.

Orographic Cumulus fractus – usually covering mountain range, large area of clouds covering both windward and lee sides of mountains.

Orographic Stratocumulus and Altocumulus (wave clouds) – form on the lee side of a mountain.

Pileus (Latin for "skullcap") is a smooth cloud found attached to either a mountaintop or growing cumulus tower.

Orographic Clouds. On Earth, large dense clouds often form in mountainous regions and hover over the tops of mountains. Air that flows over a mountain forms airwaves on the leeward side of the mountain. In the back of the wave where the air rises, cools and forms smooth elongated clouds. When moist air reaches colder upper altitudes rapidly cooling causes condensation to occur and clouds form. These clouds will linger over mountainous regions for long periods and move around very little in spite of very strong winds. They are referred to as orographic clouds. Orographic clouds on Earth are often called almond clouds or lenticular clouds [Miller and Thompson, 1970].

Doug

 

[sapblatt]

Cloud pic

This is my favorite cloud pic - over Mount Adams in October - courtesey of SherpaKroto

Cloud Pic

 

[Pete_Hickey]

...Those are actually a formation of orographic stratocumulus. Not blowing snow at all, though from afar it looks like blowing snow or spindrift. ....

Is that what this is:

http://newmud.comm.uottawa.ca/~pete/tmp/snowind.jpg

When I was on the summit, it was just clouds/fog, not snow. From further away that is what it looked like.

"I've looked at clouds from both sides now."

 

[Chip]

"I've looked at clouds from both sides now."

oh, that's funny.

EVERBODY SING NOW...
"Bows and flows of angel hair and ice cream castles in the air
And feather canyons everywhere, i've looked at clouds that way.
But now they only block the sun, they rain and snow on everyone.
So many things i would have done but clouds got in my way."