Ice falling from a cloudless sky

[Ersby]

This morning on my way to work I stopped and looked over the Thames and after a few seconds a snowball-sized chunk of ice fell in front of me onto the river bank. There were no clouds in the sky (well, some on the horizon) and it's trajectory was such that I doubt it could've been thrown from the building behind me (a theatre, set back quite a distance and which was closed).

Googling brings up a few news sites, but does anyone have a better site to explain/explore this phenomenon? Thanks.

 

[skoob]

Wikipedia has some information (but not a lot) on this phenomenon, called Megacryometeor^WPs. It seems as if it's still a mystery how those chunks of ice are formed.

 

[cloudshipsrule]

Chunks/balls of ice have been known to fall from passing airliners. Something to do with the restroom and disposing of waste. Not a pretty thought!

 

[TjW]

Yep, even in this post-cold-war world, you're still in danger from an icy BM.

 

[cloudshipsrule]

icy BM.

Nice!

 

[Ceritus]

Question.

Was it windy that day? Also did you see Cirrus type clouds or Altostratus/Altocumulus on the horizon? Also was it the River Thames you were looking at in England?

 

[Ersby]

At ground level, it wasn't that windy. The sky was clear overhead, and it was warm considering the early hour. The clouds (to the east and to the west) were Altostratus undulatus clouds (if the photos on Wikipedia are anything to go by). And it was the Thames in England. Just to the west of Waterloo Bridge, to be exact.

I thought ice from planes' toilets was supposed to be blue. Or is that also an urban myth?

 

[Ceritus]

I looked at the sembach air force weather site to view all the models and the 00Z and 12Z analysis and I did not see anything too odd going on other than the trop was pretty high up for how far north you are. Nothing screams megacryometeors because nothing seems to be that abnormal for such an abnormal phenomena to occur. For megacryometeors you need a significant drop in height of the tropopause to where it is reaching the low high levels to high midlevels normally around 18,000 to 12,000 feet while within 200nm it maintains a normal height around 30,000ft for you latitude. There needs to be significant midlevel moisture upstream of the dip in the trop moving into the dip with a very very strong divergence aloft but convergence in the midlevels and divergence on the surface to maintain stability. You normally only see this phenomena with a very deep low pressure system in the 300mb - 500mb levels but high pressure from the surface up which is what causes the significant dip in the trop.

 

[Darth Rotor]

This morning on my way to work I stopped and looked over the Thames and after a few seconds a snowball-sized chunk of ice fell in front of me onto the river bank. There were no clouds in the sky (well, some on the horizon) and it's trajectory was such that I doubt it could've been thrown from the building behind me (a theatre, set back quite a distance and which was closed).

Googling brings up a few news sites, but does anyone have a better site to explain/explore this phenomenon? Thanks.

If there was a cumulonimbus cloud, a rather tall one, within about 10-20 miles of you (on the horizon?) and if it was having a significant updraft event/build up, it is not uncommon for ice to be ejected out of the top of tall thunderheads (tops at 35-45k feet, or greater) and be found as far as 10-20 miles away.

However, given Ceritus' post about European weather, unless you observed a significant distant vertical/towering cumulus type build up, specifically orographic lifting given your location, that explanation probably won't suffice.

Anecdote: back in 1988, a good friend of mine was visually avoiding weather, a significant CB buildup over New Mexico in a T-34C at about 16000 feet, and was about 7 miles away, in clear air, when he was showered with rather large ice/hail balls which made some marked dents in the leading edge of his wings, his horizontal stabilizer, and cracked the canopy. He made a precautionary landing in New Mexico, but when all was said and done, it cost a few thousand to repair that plane before it was cleared to fly again.

DR

 

[Correa Neto]

Ice from airliner's toilets is whitish with bluish (or greenish) patches. Personal (anedoctal) experience.

Back in the early 90s I was asked by a person what to do with a chunk of weird-smelly whithish-bluish ice that fell on some nun's plantation out of the blue sky. I am a friend of a guy who worked with meteorites, and I just could not resist- "Pack it with ice inside a styrofoam box and send to Professor XXXX at XXXX. Please attach a letter saying you think its a carbonaceous condrite. No need to mention me".

Some months later while we were drinking some beer he complained about some SOB nuns who sent him a pack of frozen ***** that pestered his lab. Yes, we're still friends.

 

[fuelair]

This morning on my way to work I stopped and looked over the Thames and after a few seconds a snowball-sized chunk of ice fell in front of me onto the river bank. There were no clouds in the sky (well, some on the horizon) and it's trajectory was such that I doubt it could've been thrown from the building behind me (a theatre, set back quite a distance and which was closed).

Googling brings up a few news sites, but does anyone have a better site to explain/explore this phenomenon? Thanks.

Pure white or bluish/yellowish/brownish?

 

[Beleth]

Any schools nearby? Any school students with access to a freezer, a funnel, a couple yards of surgical tubing, and a sturdy windowframe?

 

[Dymanic]

Any schools nearby? Any school students with access to a freezer, a funnel, a couple yards of surgical tubing, and a sturdy windowframe?

I was thinking Trebuchet. Can we get more detail on the size and consistency of this iceball? If it was more of a slushball, that definitely sounds like backyard ballistics to me, but for the amateur catapultist, I can't see the advantage of a solid chunk of ice over a plain old rock.

 

[EHocking]

At ground level, it wasn't that windy. The sky was clear overhead, and it was warm considering the early hour. The clouds (to the east and to the west) were Altostratus undulatus clouds (if the photos on Wikipedia are anything to go by). And it was the Thames in England. Just to the west of Waterloo Bridge, to be exact.

I thought ice from planes' toilets was supposed to be blue. Or is that also an urban myth?

Urban Legends are not necessarily untrue.


<http://www.arsa.org/regupdate/2002/feb2002/feb12.2002.doc>

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-242-AD; Amendment 39-12646; AD 2002-03-05] RIN 2120-AA64

Airworthiness Directives; McDonnell Douglas Model DC-8 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

-----------------------------------------------------------------------
SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain McDonnell Douglas Model DC-8 series airplanes, that
requires, among other things, repetitive leak tests of the lavatory drain
systems and repair, if necessary; installation of a lever lock cap, vacuum
breaker check valve, or flush/fill line ball valve on the flush/fill line;
periodic seal changes; and replacement of ``donut'' type waste drain valves
installed in the waste drain system. This amendment is prompted by
continuing reports of damage to engines, airframes, and property on the
ground, caused by ``blue ice'' that forms from leaking lavatory drain
systems on transport category airplanes and subsequently dislodges from the
airplane fuselage.

The actions specified by this AD are intended to prevent
such damage associated with the problems of ``blue ice.''


DATES: Effective March 19, 2002.


[Full text of the above is available in the Federal Register at the
following link:
<http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=2002_register&docid=02-3311-filed>

 

[Myriad]

Urban Legends are not necessarily untrue.


<http://www.arsa.org/regupdate/2002/feb2002/feb12.2002.doc>

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-242-AD; Amendment 39-12646; AD 2002-03-05] RIN 2120-AA64

Airworthiness Directives; McDonnell Douglas Model DC-8 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

-----------------------------------------------------------------------
SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain McDonnell Douglas Model DC-8 series airplanes, that
requires, among other things, repetitive leak tests of the lavatory drain
systems and repair, if necessary; installation of a lever lock cap, vacuum
breaker check valve, or flush/fill line ball valve on the flush/fill line;
periodic seal changes; and replacement of ``donut'' type waste drain valves
installed in the waste drain system. This amendment is prompted by
continuing reports of damage to engines, airframes, and property on the
ground, caused by ``blue ice'' that forms from leaking lavatory drain
systems on transport category airplanes and subsequently dislodges from the
airplane fuselage.

The actions specified by this AD are intended to prevent
such damage associated with the problems of ``blue ice.''


DATES: Effective March 19, 2002.


[Full text of the above is available in the Federal Register at the
following link:
<http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=2002_register&docid=02-3311-filed>

Suddenly the stories about "blue ice" make a whole lot more logical sense to me than they used to. I've read several that stated or implied that dumping the waste in mid-air is a normal procedure -- which makes no sense, it's not like the process of elimination would cause the plane to weigh any more than it did before, and the consequences on the ground would be unbearable. None of them bothered to mention a leak being responsible (no, not that kind of leak).

Now, the old days of railroading is a different story. Let's just say, there was more than one good reason to tell the kids not to play on the railroad tracks.

Respectfully,
Myriad

 

[Ersby]

Any schools nearby? Any school students with access to a freezer, a funnel, a couple yards of surgical tubing, and a sturdy windowframe?

Hmm, like I said, the nearest building was a theatre. The only building nearby, really.

I wish I'd gone down for a closer look at it now. From what I saw it was white. When it landed (on sand) a few bits fell off. The reason why I don't think it was thrown was how steeply it fell. When it landed it just bounced once, pretty much straight up and back down again. If it had been thrown from the theatre behind me, it would've had enough horizontal motion to make it bounce in one direction, I think.

btw, I said west of Waterloo Bridge. I mean just east. And the Thames path at that point is lined with trees, which indicates that if it was thrown, it must have come from the roof of the theatre, since anyone throwing it from behind me at ground level would've had to have catapult it through branches. (When it fell, it didn't fall near any trees, however.)

 

[JoeTheJuggler]

but for the amateur catapultist, I can't see the advantage of a solid chunk of ice over a plain old rock.

No evidence left behind when it melts?

As for me, I like shooting big buckets of herring every now and then. Keeps the Forteans going.

 

[mhaze]

This morning on my way to work I stopped and looked over the Thames and after a few seconds a snowball-sized chunk of ice fell in front of me onto the river bank. There were no clouds in the sky (well, some on the horizon) and it's trajectory was such that I doubt it could've been thrown from the building behind me (a theatre, set back quite a distance and which was closed).

Googling brings up a few news sites, but does anyone have a better site to explain/explore this phenomenon? Thanks.

For this the reference is William Corliss, "Handbook of Unusual Natural Phenomena", specifically, pp. 506-508.

"Ice falls from a clear sky have been reported before".

It is noted that in some cases this coincides with a rocket launch, and in other cases it is speculated that the ice formed on an aircraft, then melted or broke off as the aircraft moved to a warmer altitude. As an example, a plane taking off on a slushy runway in Chicago lands in Florida. The ice falls off when the plane descends say to 15,000 feet where the temperature is above zero. Note that you would not necessarily see the aircraft either because of distance, slant ranged traveled before ground impact, clouds or other sky conditions.

Other reports in these interesting pages include actual ice meteors, which are called "hydrometeors". In numerous cases, chemical analysis of the ice was done to establish whether it was extraterrestrial.

 

[EHocking]

Suddenly the stories about "blue ice" make a whole lot more logical sense to me than they used to. I've read several that stated or implied that dumping the waste in mid-air is a normal procedure -- which makes no sense, it's not like the process of elimination would cause the plane to weigh any more than it did before, and the consequences on the ground would be unbearable. None of them bothered to mention a leak being responsible (no, not that kind of leak).

Now, the old days of railroading is a different story. Let's just say, there was more than one good reason to tell the kids not to play on the railroad tracks.

Respectfully,
Myriad

If you liked this one, I suggest you have a look at the alt.folklore.urban archive page that dispels/explains quite a number of "things I know to be true". Unfortunately the newsgroup is suffering, as most of usenet is at the moment, from off topic rubbish, but the denizens there are a font of knowledge.

Here's a couple of great resources to browse.

AFU's FAQ - http://tafkac.org/ and the "legendary" Snopes at www.snopes.com

 

[Dorian Gray]

Yep, even in this post-cold-war world, you're still in danger from an icy BM.

YOu owe me a coke, you bastige!