The Fort McMurray Fire is now so vast that it has both burned through and completely surrounded the city, its airport, and the neighboring community of Anzac 31 miles to the south. Spinning out blazes in a long tail across the green forested land of Canada, the fire now appears to cover about 40 miles of distance and 10 miles of width at its longest and widest points. A secondary fire to the northeast of the main blaze also appears to have lit off. And by the end of Saturday officials now believe the fire could cover an area the size of Rhode Island.

(Fort McMurray Fire as seen from above in the May 6 NASA/LANCE MODIS satellite shot. This huge fire now covers an approximate 10×40 mile swath of land, is throwing off numerous pyrocumulous clouds, and has spawned a secondary large fire to the northeast. In the upper left hand corner of the image above we see the bald landscapes of tar sands facilities. Smoke plume analysis indicates that the northern extent of this monstrous fire is just 3 miles to the south of the nearest tar sands facility in this shot. For purposes of scale, bottom edge of frame is 60 miles. Image source: LANCE-MODIS.)

Viewing the massive scope and extent of the blaze, one can see why an evacuation convoy of 1,500 vehicles — composed of members of the fire response team and a number of stranded evacuees from the tar sands industrial zone — was unable to flee the region earlier on Friday. BBC News reports indicated that the convoy encountered walls of flames 200 feet high and was forced to turn back to a city that finds itself surrounded with walls of flame on every side. This was the second time in two days that the evacuation convoy attempted to leave the fire zone and the second time that all ways out were found to be blocked by the fires. Thousands of people remain stranded in the fire zone to the north of the blaze and officials say it will take four days to move them once a clear pathway out is found

RCMP reported that by late Friday a third attempt from the convoy, now swelling to 2,500 vehicles, finally made its way south away from the fire zone. This attempt succeeded after encountering very dense smoke and making multiple stops through the burn scar region. Emergency evacuation leaders were concerned about fires encircling the evacuation convoy as it progressed. But fortune prevailed and the train of cars, trucks, and emergency response vehicles made it through. About three more days will be required to move the rest of the evacuees if a clear path out can be found, according to RCMP statements. (For more information on how to help those displaced by the fire look here.).

Hot Winds to Drive Fire Toward Tar Sands Saturday

GFS model forecasts indicate that temperatures will rise into the mid 80s Saturday. Yet another day of record hot readings for a climate change baked Canada. Winds are shifting toward the south. And very dry conditions will continue to worsen the already extreme levels of fire danger. With the fire now burning very close to the Athabasca oil production facility — a section of the tar sands that was evacuated yesterday due to fire encroachment — it appears that these winds will likely drive the fire toward and, possibly, into that industrial section.

(Fort McMurray fire expansion map produced by the regional municipality of Wood Buffalo and the Natural Resources Center of Canada shows the freakish rapidity with which the Fort McMurray Fire has expanded. Today, a similar northward expansion toward the tar sands industrial zone is possible.)

Over the past few days, this fire has shown an ability to move very rapidly — covering many miles of ground in just a short period. And officials estimate that the blaze could expand to an enormous 300,000 hectares (750,000 acres or nearly 1,200 square miles or an area roughly the size of Rhode Island) on Saturday. Trees surrounding the barren strip mines of the tar sands facilities provide abundant fuel for these fires and volatile chemicals produced in the facilities add an additional severe hazard. The tar sands soil is laced with bitumen — which is not typically concentrated enough to burn. However, the extreme heat of these fires may cause some of the more concentrated zones to smolder — adding to potential fuels and fire hotspots.

To this point, the biggest concern is over what may happen if the fires do get into the oil facilities. The chemical and gas facilities in the tar sands are among the largest and most volatile in the world. Many single storage units contain enough explosive compounds to generate multi-kiloton scale blasts if their container vessels are breached. And a few facilities are capable of generating enormous explosions. The Nexen Long Lake oil extraction site is one of these. And officials note that, if this particular site were to explode, it could produce a devastating blast capable of leveling trees and structures in a 14 kilometer radius. If this understanding of the officially stated estimate is correct, then it would roughly be equivalent to 30-40 million tons of TNT going off.

“We’re looking at a blast area of about 14 kilometres if that plant were to go,” said Sgt Jack Poitras in an interview with BBC at about 7:00 AM Saturday.

(Southwest winds and temperatures in the 80s will worsen fire conditions on Saturday — creating a risk that the Fort McMurray fire will sweep into the tar sands production facilities. By Sunday, another front brings with it the potential for rain — which may help firefighters contain the blaze. Image source: Earth Nullschool.)

Given the predicted weather conditions, the available fuels, and the extraordinary scope and force of the ongoing conflagration around Fort McMurray there is risk that fires will invade the tar sands production zone on Saturday. It’s also worth noting that Arctic and Northern Latitude wildfires like the Fort McMurray Fire have had a tendency to burn for a long time during recent years — lasting for many days and sometimes weeks. Adding to the tree fuels, the ground provides its own set of ignitable materials in fires so large and so hot as this one. The top layer of soil contains old leaf litter, organic material and deadfall — a layer about three feet thick that will burn in the most extreme blazes. This region of Alberta also contains deposits of discontinuous permafrost. During recent years, these permafrost zones have thawed more and more with the advance of global warming. Permafrost is carbon rich and produces its own peat-like fuel which can burn and smolder over very long periods. And there is concern that the new fires produced by climate change over Canada may serve as a mechanism for permafrost carbon release.

Record heat and climate change, therefore, provide an explosive combination of new fuels and added ignition sources for fires like the one that is now engulfing so much of this tar sands production zone. And as bad as these fires have been over the past week, Saturday may see the situation again worsen.

After the heat and dangerous wind shift on Saturday, Sunday brings with it cooler conditions and a return of northwesterly winds. Earlier forecasts had indicated a possibility of rain as well. But very dry air in the region is suppressing cloud formation and chances of precipitation are now near zero for Sunday and on through at least the next week. With such a large and hot-burning fire — rain is really the best hope that firefighters have of getting this enormous blaze under control anytime soon.

Links:

LANCE-MODIS

Canadian Wildfire Halts Evacuation Convoy

Fort McMurray Fire Updates

Earth Nullschool

How to help Fort McMurray Evacuees

Fort McMurray’s Fire to Double in Size

Canada’s Huge Fires May Release Carbon Locked in Permafrost

Hat Tip to Kevin Jones

Hat Tip to DT Lange

Hat Tip to TodaysGuestIs

Hat Tip to Vic

Hat Tip to Redsky

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