While we continue to wait for our first big snowfall of the winter season, here is some snow trivia to keep you entertained.
- Snow forms from ice crystals that are created within clouds that have
a temperature of below -0.0c. These delicate crystals form when water
vapour condenses directly into ice (known as ‘sublimation’) rather than
from supercooled water droplets that subsequently freeze. A single
snowflake consists of a number of these tiny crystals.
-
Because it contains a high percentage of trapped air (between 70-95%!)
falling snow or an accumulation of fresh snow absorbs sound, which may
explain the sometimes perceived quietness when snow is falling.
- The air trapped between the clusters of ice crystals in fresh snow
also helps to make it a good insulator, keeping ground temperatures
relatively warm.
- It is never too cold to snow, but it is
less likely to snow when temperatures are exceptionally low as very cold
air contains very little moisture.
- It is impossible for
rain to turn to snow. A raindrop will freeze into an ice pellet rather
than snow if falling through a very cold layer of air.
-
Generally speaking, the larger the snowflake, the warmer and more humid
the air mass. When falling through a relatively warm, moist layer of
air, snowflakes will partially melt on their outer layer making the
easier to clump together as they descend towards the surface.
- The idea that no two snowflakes are the same is based purely on theory rather than on hard evidence.
- Broadly speaking, the water equivalent of fresh snow is around 1/10.
For example, 10cm of fresh snow will have the water equivalent of around
1cm approximately.
- In Europe and North America, the biggest snowstorms tend to be associated with Occluded fronts.
SNOWFALL IN IRELAND
- Due to its geographical location and exposure to Polar air streams,
Donegal is Ireland’s snowiest county on average. In contrast, southern
and southeastern coastal counties experience the least snow.
-
One of the heaviest snowfalls ever recorded in Ireland occurred not in
winter, but in mid-Spring, when up to 2 foot of snow fell in parts of
Connacht and north Munster in the space of a few hours on the 1st April
1917.
- The winter of 1946-1947 is probably the snowiest
winter on record in Ireland and although the winter of 62-63 was
infamously cold, relatively little snow was recorded overall during that
season.
- Although January 1982 is famed for bringing heavy
snowfalls along parts of the east coast, less documented is the fact
that equally heavy and disruptive snowfalls affected many parts of
Ulster, Connacht and north Leinster during the previous month (December
1981)
- Based on Met Eireann data, the number of days with
observed falling and lying snow in Ireland has decreased by around 10%
since 1961.
Snow facts/data by Patrick Gordon (TMT)
