Transcript Winter-Storms-revised

Snowflakes – Pretty but Dangerous
Snowflake type depends on temperature
30 – 20 °F needles
Snowflake type depends on temperature
20 – 0 °F dendrites
Snowflake type depends on temperature
0 to -20 °F hexagonal plates
Snowflake type depends on temperature
-20 and colder hexagonal columns
Mythbuster: Does 10 Inches of Snow
Equal 1 Inch of Rain?
The quick answer: sometimes but you have
to assume that the storm is all snow.
Temperature degrees F
35 – 40
30
25
20
Snow Ratio in Inches
5:1
10:1
15:1
20:1
Winter Storms
SNOW!
Don’t forget to close your windows
Blizzard
• winds blow at 35 mph or higher
• visibility is reduced to ¼ mile
or less for 3 hours or more
Does it have to be snowing for it to be a
blizzard?
a. yes
b. no
How are winter storms created?
• Two air masses of different temperatures
and moisture levels meet along a
stationary front.
• In North America, cold, dry, Canadian air
moves south and interacts with warmer,
moist air moving north from the Gulf of
Mexico to create a winter storm.
How are winter storms created?
• An area of lower pressure
develops along the front.
This creates winds that
blow from high to low.
• As air moves toward the
low, it has nowhere to go
but up into the colder
regions of the atmosphere
where condensation
occurs.
• To the north of the storm,
where temperatures are
colder, snow falls.
Rain or Snow?
Freezing Rain
(St. Joseph’s
lighthouse)
March 13, 1993
Winter Storm of 1993
All east
coast air
ports were
closed.
Georgia
December 2001
New York City 2006
The official instrument – the ruler!
New Jersey 2006
Storm Duration
Over North America, strong winds blowing
from west to east usually move a winter
storm quickly across the continent. That's
why a winter storm rarely lasts more than
a day in one area.
One exception to this rule occurs
downwind of major bodies of water such
as the Great Lakes.
Lake Effect Snow
Lake Effect Snow
• If a strong, cold wind blows over a great length
of unfrozen water, the air acquires a lot of
moisture. This moisture turns into heavy snow
when it reaches land.
• These "lake-effect" snowstorms can last for
many days and dump huge amounts of snow.
• A lake-effect snowstorm in November 2000
dumped 25" of snow in 24 hours on Buffalo, NY.
At the storm's peak, it dumped 3" of snow per
hour!
Buffalo, NY 1977
Top 10 NJ Snow Storms since 1800
•
•
•
•
•
•
•
•
•
•
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Year
1899
1831
1947
1996
1925
2000
1888
1958
1805
1961
Inches
34
30
30
30
28
26
25
25
24
24
County
Cape May
Cape May
Monmouth
Burlington
Essex
Morris
Union
Sussex
Essex
Hunterdon
Nor’easters
• named for the winds that blow in from the
northeast and drive the storm up the east coast
• occur in the eastern United States from October
to April (those that occur early or late in season
when trees are in leaf can be particularly bad)
• dump heavy amounts of rain or snow, produce
hurricane-force winds, create high surf that
causes severe beach erosion and coastal
flooding
Nor’easters
• There are two main components to a Nor'easter:
– A Gulf Stream low-pressure system with counter-clockwise winds off
the southeastern coast of the US gathers warm air and moisture from
the Atlantic. Strong NE winds at the leading edge of the storm pull it
up the east coast.
– An Arctic high-pressure system with clockwise winds blows down
from Canada and collides with the Gulf Stream low.
There are two types of Nor'easters:
– Offshore forming - These are the storms you hear
about in the news. Metropolitan areas such as
Washington D.C, Philadelphia, New York City and
Boston are hard hit. Eventually, the system moves
far enough north that the Canadian jet stream
pushes it off the coast.
– Onshore forming - These storms are less exciting
than the offshore-forming storms. They have
gusting winds and mostly rain.
Satellite image of
the intense
nor'easter
responsible for
the blizzard of
2006. Note the
hurricane-like eye
at the center.
The Winter of 2006 – 2007
• 14 major storms, 2 more than ever before
• Only FL and CA escaped the effects
• Lasted 6 months, $6.8 billion in losses and
costs to respond, caused 214 deaths
• 6 of the 14 storms were classified as
“catastrophes” by the insurance industry
• The effects were most intense in five
sectors of the economy – property, power,
business, transportation, and government.
The Winter of 2006 – 2007
• The 2 worst storms of the year –
– The storm that hit the Plains and Midwest was
1,085 miles long and 141 miles wide. It
covered 152,600 square miles. This was 3.5
times larger than the average snowstorm.
– The Valentine’s Day storm that hit the NE
covered 186,200 square miles, 4.5 times
larger than the average. It contained a band
of freezing rain 80 miles wide.
The Winter of 2006 – 2007
• Why this season was so bad:
– Storms occurred early and late in the season
resulting in severe damage to trees and
shrubs because they were still in leaf. In turn,
the trees caused damage when they fell.
– Storms occurred in areas where they are
infrequent and local officials struggled to
respond.
– Four of the storms were extremely large.
– Storms hit urban areas.
Dolan-Davis Wave Power Index
proposed rating scale for Nor’easters
• Sea waves generated by a Nor’easter govern
the storm’s coastal impact.
• The index is computed by multiplying a storm’s
duration and wave height.
• Class 1, very common weak systems, that might
last 4 hours with 6.6 feet waves, minor beach
erosion and little or no property damage.
• Class V, very rare extreme systems, that might
last 4 days or longer with 23 foot waves that
produce extreme beach erosion and cause
regional property damage.
Weather.com gets in trouble with the
National Weather Service
Winter Storm Names 2012 – 2013
Athena
Helen
Orko
Virgil
Brutus
Iago
Plato
Walda
Caesar
Jove
Q
Xerxes
Draco
Khan
Rocky
Yogi
Euclid
Luna
Saturn
Zeus
Freyr
Magnus Triton
Gandolf
Nemo
Ukko
Ice storm
• A severe ice storm hit Missouri, Kansas,
Nebraska, Iowa and Illinois.
• Ice covered an area the size of California.
• Missouri declared an emergency and put
the National Guard on alert.
• Thousands of people slept in airports due
to delayed and cancelled flights.
• The airport in Tulsa, OK had no electricity.
Ice Storm – December 2007
University of Oklahoma
Utility crews struggle to restore power to over 1 million homes. In
Oklahoma, this was the worst blackout in state history.
Winter of 2013 - 2014
This is only one of
the 20 winter
storms for which
the Off ice of the
New Jersey State
Climatologist
collected data and
created maps.
Winter of 2013 - 2014
Winter of 2013 - 2014
• Mid-Atlantic, NE and New England temperatures averaged
below normal
• Jan and Feb were coldest months compared to average
• Dec and Feb were wettest months, with well above normal
precipitation
• even distribution of precipitation up and down the East
Coast of between 12 and 14 inches
• all stations saw above average snowfall for the period
• Philadelphia to New York City corridor saw highest totals
compared to average
• Dec-Feb, Philadelphia saw over 300% of typical snowfall
accumulation
• many locations doubled or tripled their snowfall compared to
last year!
What is the number
one cause of deaths
during winter storms?
Winter Storm Dangers
• Traffic accidents is
#1!
• Heart attacks while
shoveling
• Hypothermia from
exposure to cold
• Frost bite due to wind
chill
Why is ice slippery?
• Weight adds
pressure that
makes ice melt.
• People and cars
are heavy so they
create a thin layer
of water between
the ice and the
shoe or tire.
Winter Storm Safety
• Find shelter; stay dry; cover all skin; get
out of the wind
• Build a fire surrounded by rocks
• Do not eat snow; melt it first
• Stay in your car with window open for air
• Make sure exhaust pipe is not blocked
• Tie red flag to car
• Exercise to stay warm
• Run the engine for 10 minutes each hour
Avalanches
• An avalanche is a
mass of tumbling
snow.
• Can travel at up to 200
mph
• Destroy everything in
their path
• 1200 in US each year
The Children’s Blizzard 1888
What made the storm so deadly was the timing
(during work and school hours), the
suddenness, and the brief spell of warmer
weather that preceded it. The very strong winds
and the powdery nature of the snow reduced
visibilities on the open plains to zero. People
ventured from the safety of their homes to do
chores, go to town, or attend school. As a result,
thousands of people—including many
schoolchildren—got caught in the blizzard. The
death toll was 235.
1888
The Children’s Blizzard 1888
• Lois Royce found herself trapped with 3 students in the
schoolhouse. By 3 p.m., they had run out of heating fuel. Her
boarding house was only 82 yards (75 m) away, so she
attempted to lead the children there. However, visibility was
so poor that they became lost and the children, two nineyear-old boys and a six-year-old girl, froze to death. The
teacher survived, but her feet were frostbitten and had to be
amputated.
• Etta Shattuck, a 19 year old teacher, got lost on her way
home She sought shelter in a haystack but was trapped
there until her rescue 78 hours later. She died on February 6
due to complications from surgery to remove her frostbitten
feet and legs.
• In South Dakota, two men tied a rope to the closest house
and headed for the school. There, they tied off the other end
of the rope, and led the children to safety.
• Minnie Freeman safely led 13 children from the school to her
home, one half mile (800 m) away. She took them to the
boarding house she lived at about a mile away and all of her
pupils survived.