What is heavy? What is light?

irish1967

Just a thought and I'm not sure there is a satisfactory way of doing this but I'm sure someone might think of something.
During recent snow events etc reporting of snow location was excellent but one thing that may gave distorted the situation was that posters definition of light, moderate, heavy, very heavy, blizzard and whiteout all varied. The same could be said during wind event and even rainy ones to some extent.
Is there any way of setting up a sticky reference thread so standard definitions (using videos maybe) could be used. Kinda like a boards weather video beaufort scale. I'm sure there are YouTube videos of nearly every situation at this stage.
Just an idea but one I think that could standardize the reports here.

Irish

Tom Cruises Left Nut

The Boards "Dandruff Scale"

It won't work as the hoardes that come in during events won't read it and will post what thye think.

My advice is to consider heavy the new light.
So when it's really really heavy use an acronyms like Humungous flakes.
Heaviest snow I've ever seen.
Visibility very poor
Flakes the size of dinnerplates
Dinnerplating it now...
An inch in the last 20 minutes etc etc

A flurry is a blizzard to most people 'cause they know no better.

Mobhi1

I'm usually reluctant to say how heavy rain or snow is because, as you say, it means different things to different people.

nacho libre

We sadly very rarely get blizzard conditions at lower levels in Ireland. So any post reporting blizzard conditions from their location was mistaken.

A blizzard is defined as winds blowing at a minimum speed of 35 miles (56 kilometers) per hour and visibility of less than one-quarter mile.


During the last cold spell, between 4:00 pm and 8pm on December 17th, four and half inches of snow fell here. I've never seen snow accumulate at such a rate before - even during the snow event of December 2000 the snow did not accumulate at such a rate. My posts at the time may have seen hyperbolic to many, but I think I was actually giving a fairly accurate account of conditions.
It's kind of sad actually recalling that epic day because i doubt i'll see anything as brilliant as that again this winter.

Iancar29

nacho libre wrote: »

We sadly very rarely get blizzard conditions at lower levels in Ireland. So any post reporting blizzard conditions from their location was mistaken.

A blizzard is defined as winds blowing at a minimum speed of 35 miles (56 kilometers) per hour and visibility of less than one-quarter mile.

I said this a few times during the cold snap. I was kinda gettin annoyed at the amount of people stating it when to any practical observer it was only light -moderate .

But ye, it was all part of the excitement of the days also.
ALL GOOD FUN MAY I SAY....:)

PS, this weather 2day is soooo boring!

greysides

Curious thread. I was actually of the belief that the weather definitions were pretty tightly sown up. At least, as far as the words ME use during their forecasts.

Mobhi1

The definitions are fairly tight but most people wouldn't know what they were or how to compare what they're seeing with the definition.

irish1967

Oh I am sure ME's forecasts are written word perfect ( even if their spelling leaves a lot to be desired at times) and that their terms of reference are set in stone.
I guess descriptive terms on a thread during the excitement of a snow event would be rather hard to standardize for the sake a clarity.

Deep Easterly

Light Snow:
Snow in which the visibility from the snow is still greater than 0.5 mile

Snow:
Snow in which the visibility from the snow is in a range from 0.25 and 0.5 mile

Heavy Snow:
Snow in which the visibility from the snow is less than 0.25 mile



http://www.theweatherprediction.com/habyhints2/434/

Harps

Hard to put the description in words obviously but I'd report heavy snow whenever I get that thick fluffy stuff that accumulates quickly. I've never really said anything more than 'heavy'

Moderate, smaller flakes but still falling as a reasonably heavy rate

Light, obviously anything below that

I'm not sure what a blizzard actually looks like but on the 15th of December it must have been pretty close here, persistent strong winds and extremely heavy snow that accumulated 15-20cm in 6 hours

Su Campu

And a heavy SNOWFALL is defined as 4 inches or more in 12 hours, or 6 inches in 24 hours (level snow - not including drifts), or 50mm or more in liquid equivalent in 24 hours. Heavy RAINFALL is 50mm or more in 24 hours.

Here is the official WMO guide for observing present weather. Go to page 323.

http://www.wmo.int/pages/prog/www/IMOP/publications/CIMO-Guide/CIMO%20Guide%207th%20Edition,%202008/CIMO_Guide-7th_Edition-2008.pdf

Mixed precipitation of rain and snow
The same as for snow (since the rain/snow ratio
is not subject to any measurement, a simple
choice should be made).
Hail: The same as for rain.
Ice pellets: The same as for snow.
Freezing phenomena: The same as for the
non‑freezing phenomena.

Guide for approximating the intensity of snow
Light: Snowflakes small and sparse; in the
absence of other obscuring phenomena, snow at
this intensity generally reduces visibility, but to
no less than 1 000 ms
Moderate: Larger, more numerous flakes generally
reducing visibility to between 400 and
1 000 m.
Heavy: Numerous flakes of all sizes generally
reducing visibility to below 400 m.

nacho libre

Harps wrote: »

Hard to put the description in words obviously but I'd report heavy snow whenever I get that thick fluffy stuff that accumulates quickly. I've never really said anything more than 'heavy'

Moderate, smaller flakes but still falling as a reasonably heavy rate

Light, obviously anything below that

I'm not sure what a blizzard actually looks like but on the 15th of December it must have been pretty close here, persistent strong winds and extremely heavy snow that accumulated 15-20cm in 6 hours

there were strong winds here too and the snow was heavy, but it wasn't blizzard conditions. Going by Su Campu's guide what we got on December 17th would be fairly described as heavy snowfall at times. Lord knows how long it will be before we see precipitation intensity like that from the north again.

waterways

Deleted User wrote: »

It won't work as the hoardes that come in during events won't read it and will post what thye think.

Tell them Met Office gives the equivalent of thirty centimetres of fresh fallen snow as 25 mm of rainfall.

Give them this scale for heavy precipitation and ask them to measure the snow depth every two minutes.

Steopo

Informative posts as ever but here is a shot a something a little less technical

Boards.ie Snow gauge for Ireland

Light snow – threads containing words such as “moderate snow here, nice dusting, marginal, very small flakes, flurry, don’t think it will stick not sticking or beginning to stick, sprinkling, sleet, disappointing, dew point not looking good, downgrade, nice covering”
Moderate – threads containing words such as “heavy snow here
,yee hah SNOW, where’s the ruler, pelting down here, bucketing down, heaviest snow I’ve ever seen, intensified, substantial covering, accumulating, this could be epic, cm’s,
Heavy – threads containing words such as “blizzard conditions here, epic, snowmaggedon, 1982, 1947, OMG I didn’t think I’d ever live to see this much snow, where can you buy a snow shovel, streamers, raintoday.co.uk, whiteout, travel chaos, MT your a legend, ice age, airport closed, inches”
Blizzard – internet forums did not exist so no reference point

Pangea

nacho libre wrote: »

We sadly very rarely get blizzard conditions at lower levels in Ireland. So any post reporting blizzard conditions from their location was mistaken.
.

I think people shouldnt get too caught up in whats the proper terms.
On many occasions i reported blizzard like conditions, yes maybe what we had didnt qualify as a proper blizzard, but to the non weather expert a blizzard is when there is heavy snow falling and when theres strong wind accompaning it with bad visibilty, to go into technicalities about what qualfies as a proper blizzard and winds speeds is overkill imo.

waterways

Deep Easterly wrote: »

Light Snow:
Snow in which the visibility from the snow is still greater than 0.5 mile

Snow:
Snow in which the visibility from the snow is in a range from 0.25 and 0.5 mile

Heavy Snow:
Snow in which the visibility from the snow is less than 0.25 mile

Some additions:

Very Light Snow:
The visibility is not greater than two miles and you can count the flakes.

Very Heavy Snow:
Snow in which the visibility from the snow is less than to the car in front of you.

Blizzard:
Where is the car?

Oscar Bravo

Heavy Snow=800+ users in the Weather Fourm. Good thread this,i think during the summer it was discussed too,in rain terms,of course.i.e some Met Stations were reporting HVY RAIN and then others were reporting MOD RAIN,however the HVY RAIN total had eg 2.7mm and the MOD RAIN total had 3.1mm for that particular hour.

Su Campu

Oscar Bravo wrote: »

Heavy Snow=800+ users in the Weather Fourm. Good thread this,i think during the summer it was discussed too,in rain terms,of course.i.e some Met Stations were reporting HVY RAIN and then others were reporting MOD RAIN,however the HVY RAIN total had eg 2.7mm and the MOD RAIN total had 3.1mm for that particular hour.

But the 2.7mm would only have fallen in a short period of time, not over the whole hour. The rain reported would be a reference to the rainfall RATE, not the hourly total. A "heavy" rainfall rate is at least 10mm per hour, or around 0.17mm per minute. The rain in that case may have only lasted for 15 minutes to give the 2.7mm total.

nacho libre

Pangea wrote: »

I think people shouldnt get too caught up in whats the proper terms.
On many occasions i reported blizzard like conditions, yes maybe what we had didnt qualify as a proper blizzard, but to the non weather expert a blizzard is when there is heavy snow falling and when theres strong wind accompaning it with bad visibilty, to go into technicalities about what qualfies as a proper blizzard and winds speeds is overkill imo.

You're just trying to cover yourself for giving misleading reports:D I was just pointing out that we rarely do get blizzards in Ireland.
I agree that getting caught up in precise terms takes the fun out of it.
However a qualified meteorologist might see things differently.

Pangea

nacho libre wrote: »

You're just trying to cover yourself for giving misleading reports:D I was just pointing out that we rarely do get blizzards in Ireland.
I agree that getting caught up in precise terms takes the fun out of it.
However a qualified meteorologist might see things differently.

Lucky we are not qualifed meteorologists then.
Blizzard like conditions is not misleading , Met eireanns forecasts even used that term in the past cold spell
Even the last day when it was snowing here on Saturday the snow was coming down heavy nearly at a right angle being blown by the wind, certainly was blizzard like.

nacho libre

Pangea wrote: »

Even the last day when it was snowing here on Saturday the snow was coming down heavy nearly at a right angle being blown by the wind, certainly was blizzard like.

describing conditions as blizzard like when they are nothing of the sort is misleading;) based on the weather conditions at that time, what you got on Saturday wasn't even close to a blizzard

Pangea

nacho libre wrote: »

describing conditions as blizzard like when they are nothing of the sort is misleading;) based on the weather conditions at that time, what you got on Saturday wasn't even close to a blizzard

On Saturday the snow and conditions where blizzard like for the short period of time it did snow, take it or leave it. So I do not know why you continue to say I was misleading. There where no big accumulations I was describing the way the snow was coming down very heavy and with strong winds.
If you where here maybe you would have thought differently since you where not you cant say that it was nothing of the sort.
I didnt say I had a blizzard , I said it was like a blizzard out there.

nacho libre wrote: »

I agree that getting caught up in precise terms takes the fun out of it.

Exactly.

nacho libre

Pangea wrote: »

On Saturday the snow and conditions where blizzard like for the short period of time it did snow, take it or leave it. So I do not know why you continue to say I was misleading. There where no big accumulations I was describing the way the snow was coming down very heavy and with strong winds.
If you where here maybe you would have thought differently since you where not you cant say that it was nothing of the sort.
I didnt say I had a blizzard , I said it was like a blizzard out there.

I don't have to have been there to know you are probably wide of the mark in suggesting that it was blizzard like since there was not a force 6 wind in Donegal at the time. If you had winds in excess of 30 miles an hour and visibility was reduced to nearly 400 metres then it would be correct to say it was blizzard like, but as i've said since weather conditions were nothing like that at the time in Donegal it is misleading to say it was blizzard like in my opinion.

I'm not getting caught up in technical terms, i'm simply restating that blizzards, and conditions even close to a blizzard, are rare in Ireland at lower levels. You seem to want to dispute this for some reason.

Supercell

Heavy snow looks like fog, visibility around 100 metres or less. Then again I used to live in the Wicklow mountains so my definition of light is probably a Cork persons estimate of heavy :pac::pac::pac:

Rebelbrowser

Supercell wrote: »

Heavy snow looks like fog, visibility around 100 metres or less. Then again I used to live in the Wicklow mountains so my definition of light is probably a Cork persons estimate of heavy :pac::pac::pac:

Supercell, one ffarrell7 per forum please!

Deep Easterly

nacho libre wrote: »

I'm not getting caught up in technical terms, i'm simply restating that blizzards, and conditions even close to a blizzard, are rare in Ireland at lower levels. You seem to want to dispute this for some reason.

In fairness though Nacho, most people are not aware or concerned about the technical aspects of what constitutes a blizzard or not. Of course there is reasoning behind meteorological critieras such but when people see heavy snow blowing horizontally in a strong wind it is only natural that they will call it a blizzard; they may well be wrong by meteorological standards but at the same time totally right by there own, which matters just as much to them.


Anyway, Pangea may not have experienced a full on blizzard by official standards but whether we like it or not, he still lives in the snow capital of Ireland!



Map showing average No. of days with snow over Ireland in an average year: (based on 61-90 average)



Map taken from:
"Climates of the British Isles: present, past and future" ( Elaine Barrow, Michael Hulme: 1997)



We must bow our heads in shame!

steveLFC24

I don't see the problem with using the term 'blizzard like'. The keyword here is 'like'. To use the word blizzard on its own would be incorrect (in low levels places in Ireland anyways). 'Blizzard like' from my point of view suggests heavy blowing snow with poor visability, though with less wind, better visability and lighter snow than you would see in a proper blizzard. So its blizzard like, but not quite a blizzard. Ok I'm rambling, I'll stop now :pac:

gbee

I saw a blizzard a few years ago in Cork. It was Christmas Eve and I was doing the Santa photos and at lunch the Douglas Village SC started banging violently.

The roof lifted and crashed down and everyone ran terrified, the suddenness was shocking, the ferocity was terrifying.

Poles bent ion the car park, cars moved around, umbrellas became missiles, shopping carts became barricades, trees, tree limbs and branches came flying along. Winds were over 100MPH sustained.

The roof right over our Santa hut blew off and the hut destroyed. I had to evacuate Santa's Elves and myself. As we drove to the top of Maryborough Hill we were blocked by fallen trees or walls.

I tried a few routes, delicately negotiating under fallen trees and eventually made it up Mount Oval, a narrow pine lined avenue and delivered my charges to their homes.

The next morning that avenue was totally blocked and remained that way for a week or more ~~ scary.

It was a blizzard, violently driving snow/sleet/hail ~ just like you'd see in the 'Tornado Chasers' ~ winds over 100MPH take on a chocking charismatic and threaten to just suck the life out of you.

Pangea

nacho libre wrote: »

I don't have to have been there to know you are probably wide of the mark in suggesting that it was blizzard like since there was not a force 6 wind in Donegal at the time. If you had winds in excess of 30 miles an hour and visibility was reduced to nearly 400 metres then it would be correct to say it was blizzard like, but as i've said since weather conditions were nothing like that at the time in Donegal it is misleading to say it was blizzard like in my opinion.
I'm not getting caught up in technical terms, i'm simply restating that blizzards, and conditions even close to a blizzard, are rare in Ireland at lower levels. You seem to want to dispute this for some reason.

Nacho you are the one disputing my posts
You are constantly challenging my posts saying I was misleading.
We already agreed on what the term a proper blizzard was, I already said that what I had wasnt a blizzard ,I was merely describing the way the snow and winds where that it was like a blizzard, Those are two different things.
Oh but you are getting caught up in techinal terms because you just talked about exact wind speeds and visibitly distances to qualify even for a blizzard like condtion , never mind a full blown blizzard!

I am being forced to repeat myself because you are obviously missing the point.
If its very windy and snowy people are going to say its like a blizzard out there and not going to worry about the windspeeds and visibilty scale. Get over it. We are all not weather experts.
If its stormy out there people might say its like a hurricane.

I have said all I have to say. If you think my posts are misleading then come to Donegal on a windy snowy day or click the ignore button. Blizzard like conditions are not as rare as you think here. When its stormy here in West donegal you might have a gentle breeze in inland Mayo.


Its all in my first post

Pangea wrote: »

I think people shouldnt get too caught up in whats the proper terms.
yes maybe what we had didnt qualify as a proper blizzard, but to the non weather expert a blizzard is when there is heavy snow falling and when theres strong wind accompaning it with bad visibilty, to go into technicalities about what qualfies as a proper blizzard and winds speeds is overkill imo.

Mobhi1

Wikipedia's definition of blizzard (doesn't even have to have heavy snow!):

A blizzard is a severe storm condition characterized by low temperatures[vague], strong winds, and can include heavy snow. By definition, the difference between blizzard and a snowstorm is the strength of the wind. To be a blizzard, a snow storm must have winds in excess of 56 km/h (35 mph) and reduce visibility to 400 metres (1,300 ft) or less and must last for a prolonged period of time — typically three hours or more.[1] Ground blizzards require high winds to stir up already fallen snow.

Blizzards can bring near-whiteout conditions, and can paralyze regions for days at a time, particularly where snowfall is unusual or rare. The 1972 Iran blizzard, which caused approximately 4000 deaths, was the deadliest in recorded history.

Deep Easterly

Well, big full-on blizzards are a rare occurance in Ireland at the best of times but here is an account of one that occurred on the 3rd-4th March 1965:






Noon Chart for the 3rd of March '65. Arctic blast:






Backing north-easterly on the 4th as a Polar depression moved south over the country:







Extractions & Images c/o The Irish Times

nacho libre

Deep Easterly wrote: »

In fairness though Nacho, most people are not aware or concerned about the technical aspects of what constitutes a blizzard or not. Of course there is reasoning behind meteorological critieras such but when people see heavy snow blowing horizontally in a strong wind it is only natural that they will call it a blizzard; they may well be wrong by meteorological standards but at the same time totally right by there own, which matters just as much to them.


Anyway, Pangea may not have experienced a full on blizzard by official standards but whether we like it or not, he still lives in the snow capital of Ireland!



Map showing average No. of days with snow over Ireland in an average year: (based on 61-90 average)



Map taken from:
"Climates of the British Isles: present, past and future" ( Elaine Barrow, Michael Hulme: 1997)



We must bow our heads in shame!

You're right of course paddy1. I realise now I was coming across as a pedantic ass