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Terrible
Thunderstorms of Fire Over Canada as Arctic Territory Continues
Record Burn
7
August, 2014
They
call them pyrocumulonimbus. In layman’s terms — fire
thunderstorms.
*
* * * *
At
the surface, a very large wildfire covering tens of square miles or
more can produce quite a lot of heat. The smokey column cast off by
the burning blaze rises, generating lift in the atmosphere even as it
seeds the air with smoke — nuclei to which water droplets can
adhere and from which clouds can form. The rising column contacts
water vapor, pushing a vast head of it upward. As this heat-driven
column hits the upper reaches of the troposphere, it cools, and the
water vapor condenses to the readily available smoke aerosols.
This
process produces what is called a pyrocumulus cloud or a fire cloud —
a smoke and heat fed version of the normal and far less ominous puffy
cumulus clouds we are so accustomed to seeing during summer
afternoons. In the pyrocumulus, if the updraft is intense enough, if
the fire beneath the cloud strong enough, it erupts into a
pyrocumulonimbus — a fire thunderstorm rife with lightning and, if
the firefighters are lucky, rain as well.
On
August 5, 2014, NASA got an amazing shot of a pyrocumulonimbus cloud
exploding over the massive and anomalous wildfires still raging in
Arctic Canada. See that horrific boiling cloud stack above fire and
smoke in the center-left of the image below? That’s a fire
thunderstorm:
(Explosive pyrocumulonimbus cloud near Great Slave Lake on August 5 of 2014. Marked off red areas in the image indicate fire boundaries for individual fires. For reference, Buffalo Lake in the lower left corner is about 35 miles long from end to end. Image source:NASA.)
Dark
Carbon Delivery Mechanism
NASA
keeps a close watch on fire thunderstorms for a number of reasons.
First, they are an indication of the heat updraft intensity rising
off the fire beneath. And though they can result in beneficial rains,
the storms are, many times, dried out by an over-abundance of smoke.
As a result, a dry fire thunderstorm can add to fire hazard by
casting off bolts of fire-setting lightning while begrudgingly
holding back their moisture load.
Lastly,
and perhaps most hauntingly, the fire thunderstorm is a delivery
mechanism for black and brown carbon aerosols to the stratosphere,
where they can do considerable damage. For if the updraft in the fire
thunderstorm is powerful enough, water vapor droplets laden with heat
intensifying dark carbon can break the troposphere boundary and enter
the stratosphere. There, these dark aerosols trap heat and intensify
global warming.
NASA
studies have shown that dark aerosols in the stratosphere can have a
global warming potential impact up to a million times that of a
similar volume of CO2, so even a small amount lofted by fire
thunderstorms could have a substantial effect. And the recent very,
very intense fires in the Arctic region may well be providing an
ominous and very widespread mechanism for just such a dangerous
delivery.
Fire
Thunderstorms Over Record Arctic Burn Zone
The
region where this fire thunderstorm erupted on August 5 is
experiencing what is likely the most intense Arctic burn Canada has
ever seen. Since the start of this year, and as of August 6, about
2,850,000 hectares (11,000 square miles) have burned in the Arctic
Northwest Territory (NWT) alone. This burn area so far for this one
territory is almost twice that for the whole of Canada during an
average year through early August. For the NWT, it represents an epic
burning more than 15 times that of the 15 year average (which is
usually 185,000 hectares by this time of year).
To
say that such a major burn for an Arctic region normally resistant to
wildfires is extraordinary may well be an understatement. The blazes
this year cast off smoke that covered much of the North American
Continent, crossed Greenland and has ridden weather systems around
the globe. Many fires have burned non-stop for more than a month,
burning the soil and thawed permafrost once the forest fuels are
exhausted.
Climate
models show an increased prevalence of Arctic wildfires as human
warming continues to advance into the Arctic this Century. As of the
mid 2000s and throughout this decade, we have seen very intense
wildfires raging in Arctic Canada, Alaska, Scandinavia, and Siberia.
(Massive wildfires still burning in Siberia on August 6, 2014. For reference, bottom edge of frame is about 300 miles. Image source: LANCE-MODIS.)
That
these fires are an amplifier to human driven warming is probably a
given. They dump extra CO2 and methane into the atmosphere, they burn
both the more recent forest carbon store and the far older store in
the soil, they break the permafrost cap, opening up new fuels for
fires in subsequent years and providing avenues for methane and CO2
release, they dump dark carbon over low albedo surfaces such as ice
sheets and sea ice, and they produce fire thunderstorms with the
potential to inject dark carbon into the stratosphere.
While
taking into account the entire Arctic system feedback to human caused
climate change will likely be a monumental task, the mechanism of
Arctic wildfires to tap and deliver the massive land-based Arctic
carbon store to the atmosphere in various ways may be one of the
critical elements in the overall feedback system. One that to any
rational observer appears to be energetically emerging now. An
expanding Arctic outburst of summer smoke and flame that is
terrifying to watch.
Links:
UK
severe weather warnings
as hurricane Bertha crosses
Atlantic
Almost
month's rain could fall in few hours in parts of south on Sunday,
with forecasters warning of flooding and strong winds
7
August, 2014
Forecasters
have warned that parts of Britain can expect almost a month's
rainfall in the space of a few hours and strong winds, especially in
the south, on Sunday, with the risk of flooding as the remains of
hurricane Bertha reach this side of the Atlantic.
The
Met Office has issued a severe weather warning for rain for Sunday
covering Wales and southern England, bringing at least a temporary
end to a glorious summer. "There is the potential for widespread
rainfall totals of more than 50mm and coastal gusts of over 60mph,
along with large waves," said the Met. "However, the system
may pass harmlessly to the south of the country or spread heavy rain
even further north, and the public are advised to keep up to date
with warnings."
The
average rainfall for the whole of August in England is 69mm.
The
Met has been tracking Bertha for the past few days, trying to
determine its strength and direction. It is a notoriously difficult
task and the forecasts have to be adjusted according to the data.
"The transition from a tropical to an extra-tropical feature is
a particularly hard one to forecast with confidence, and computer
models continue to differ in the location and intensity of the
resulting depression, which is expected to pass over, or close to,
the UK from early on Sunday," the Met said.
On
Wednesday, forecasters thought Britain was unlikely to suffer serious
after-effects from the hurricane, which battered the Caribbean
islands with gusts of more than 90mph, leaving thousands of homes
without power. They said it was debatable whether what would arrive
was even ex-Bertha as the storm weakened to such an extent as it
crossed the Atlantic.
On
Thursday, however, they changed tack, warning of heavy rain and a
possible risk of flooding.
"On
Sunday and Monday, a combination of high spring tides and strong
westerly winds brings a possible risk of flooding to the south-west
coast of England and along the Severn estuary, while heavy rain may
also lead to localised surface water flooding in parts of southern
and central parts of England," said Craig Woolhouse, flood risk
manager at the Environment Agency.
"However,
the forecast remains uncertain so we advise people to regularly check
the flood risk situation over the next 48 hours."
On
Friday, parts of Britain will see some heavy rain that is not linked
to Bertha.
Bertha,
the second hurricane of the 2014 Atlantic hurricane season, began as
a tropical storm on 31 July about 275 miles east-southeast of
Barbados. It brought some welcome rainfall to drought-suffering parts
of Puerto Rico, the Virgin Islands, and eastern Hispaniola.
Much
of Puerto Rico picked up at least 25mm of rain, with some interior
mountainous locations estimated to have topped 254mm, with reports of
partial road collapses.
Bertha's
impact on the US took the form of high surf and "rip"
currents that move directly away from the shore. One man drowned due
to rip currents Florida.
Hawaii
prepares for first direct hit from hurricane in 22 years as second
storm looms
The
Big Island of Hawai’i is bracing for a double whammy of hurricanes
to make landfall between Thursday and Monday, according to the
National Weather Service. The last time the archipelago took a direct
hit from a hurricane was 1992.
RT,
7
August, 2014
Iselle,
a Category 1 storm, is forecast to arrive on Hawai’i Thursday night
local time, then weaken and continue on to the rest of the islands by
Friday, according to Weather.com. The storm defied expectations that
it would weaken to a tropical storm over the course of the day
Wednesday. Iselle is roughly 300 miles east-southeast of Hilo, on the
island’s eastern corner. It is moving quickly, at 15-20 mph.
"The
real effects will probably be felt on the Big Island starting around
noon" (6 p.m. ET) on Thursday, Norman Hui, a National Weather
Service (NWS) meteorologist in Honolulu, told USA TODAY. "The
worst of it will be tonight. This storm is holding together pretty
well."
The
storm is currently weakening, and forecasters are unsure whether it
will make landfall as a hurricane or a tropical storm, Weather.com
reported. At 7 a.m. Hawaiian time (5 p.m. GMT), Iselle had maximum
sustained winds of 80 mph, placing it in the middle of the Cat-1
range (74-95 mph) on the Saffir-Simpson scale, according to the
Central Pacific Hurricane Center (CPHC).
Even
still, Iselle is expected to bring heavy rains totaling 5 to 8
inches, winds gusting up to 85 mph, and flooding, while waves could
grow up to 28 feet, according to the NWS.
“It’s
a fairly potent hurricane by Hawaiian standards,” said Weather
Channel meteorologist Kevin Roth.
Meanwhile,
forecasters are also keeping an eye on Hurricane Julio, currently a
Cat-2 (defined as winds 96-110 mph). That storm is lurking over 1,000
miles each of the Hawaiian archipelago, with sustained winds of 100
mph. Its current track has it hitting the islands late Sunday or
Monday, but it is too far away to make a firm prediction of its
course, Hui said.
With
the close proximity of the two major storms, as well as a
4.3-magnitude earthquake that struck seven miles (11 km) west
northwest of Waimea (and 50 miles from Hilo) on Thursday morning,
residents are stocking up on water and non-perishable items.
Honolulu
school teacher Gina Nakahodo told Reuters she had felt calm until she
reached the empty water aisle of her local grocery store early on
Tuesday.
"We've
had so many storms that have passed us by, but with these two back to
back you begin to worry. Then all of the sudden the aisles are empty
and there's no water and it makes your heart pound a little,"
Nakahodo said.
Willis
Sanchez leaves the local hardware store with sheets of plywood to
board up his windows as a hurricane and a tropical storm approach the
Hawaiian islands, in Mililani, Hawaii, August 5, 2014.(Reuters / Hugh
Gentry)Willis Sanchez leaves the local hardware store with sheets of
plywood to board up his windows as a hurricane and a tropical storm
approach the Hawaiian islands, in Mililani, Hawaii, August 5,
2014.(Reuters / Hugh Gentry)
Hurricanes
‒ especially major ones ‒ are rare on the Hawaiian islands. The
last direct hit came from Iniki in 1992, the deadliest and by far the
costliest hurricane to ever strike the state. Adjusted for inflation,
Iniki caused roughly $3 billion in damages, Weather.com reported.
More than 14,000 homes were affected, with 1,421 destroyed and 5,152
with major damage, and four people died.
“While
wind was the cause of most of the damages, storm surge and waves
obliterated many structures along Kauai’s southern shore,"
Weather.com said. “The other main Hawaiian Islands including Oahu
were affected by Iniki, mainly in the form of high surf but also with
some wind damage, but Kauai took the full force of the hurricane.”
The
archipelago was only hit twice before Iniki’s arrival, by Iwa in
1982 and by Dot in 1959 (just before Hawaii became a state); both
were Category 1 storms. Iwa had 90-mph winds and caused $312 million
in damages on the islands of Niʻihau, Kauaʻi and Oʻahu. One person
died. Dot caused $6 million worth of destruction, and indirectly led
to two deaths, according to the San Francisco Gate.
Because
of the infrequency of the major storms, meteorologists don’t know
how the mountains on Hawai’i will affect Iselle’s impact on the
island.
"The
Big Island has two peaks of up to 14,000 feet. If the hurricane makes
a direct hit over the Big Island, how much of a blocking effect that
has we don't know," Ray Tanabe, acting director for the NWS in
the Pacific Region, told Reuters.
Mike
Cantin, another NWS meteorologist, told the Associated Press that the
Big Island’s terrain should help break up the storm’s strength,
weakening it to a tropical storm as it heads on to Maui and Oahu.
"The volcanoes on the Big Island will do a number on the
system," he said.
The
biggest problem with the terrain ‒ and the state’s distance from
the mainland ‒ is its potential for impacting disaster relief
efforts.
"With
Hawaii's remoteness, it could be as long as a week before a full
disaster relief operation can be initiated," the Honolulu
Department of Emergency Management said in a statement.
HDEM
has released a document of frequently asked questions for residents
to prepare for the storms. The department is recommending residents
to prepare a seven-day disaster supply kit.
4.5
Earthquake Strikes
Hawaii as Hurricane Iselle
Looms
http://blog.weathernationtv.com/2014/08/07/4-5-earthquake-strikes-hawaii-as-hurricane-iselle-looms/
As
residents of Hawaii — especially the Big Island — prepare for the
late Thursday landfall of Hurricane Eselle, they’re dealing with
another natural hazard as well. A 4.5 earthquake struck on the island
of Hawai’i around 6:24 a.m. local time, jolting already on-edge
residents.
The
quake, centered about 7 miles west-northwest of Waimea, was
relatively shallow — only about 9.5 miles below the surface. At
this point no damage is being reported and the Pacific Tsunami
Warning Center tweeted that no tsunami warning would be issued.
No #tsunami from local 4.2 earthquake in the Kohala Region of the Big Island, Hawaii. #PTWC http://ptwc.weather.gov/?region=2&id=hawaii.EQIHWX.2014.08.07.1626 …
Hawaii
is no stranger to seismic activity, as the island state sits on top
of a mid-tectonic plate plume of magma. Movement of subterranean
magma is most often the cause of earthquakes in Hawaii, since it’s
so far removed from fault lines. On average, Hawaii has about 50
earthquakes per year. Making the Aloha State the third most
seismically active state, only behind Alaska and California.
Kiluea,
which is also on the Big Island, is the most active volcano on Earth
and has been erupting since January 3, 1983.
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