Predicted rain and cooler temperatures this week in Australia could slow the spread of the bushfires in Victoria and New South Wales. The heaviest rain will be on the east coast where some areas could receive over two inches while the forecast on the west side of the two states is for much less or perhaps none.
The rain is the product of a deep inland trough drawing humid air into the system.
Small amounts of rain will not put out the fires, but could make them partially dormant for a period of days, giving firefighters time to regroup and construct firelines on portions of the perimeters. But many of the fires are far too large to ever be completely encircled by firelines.
Some of the rain will come in the form of thunderstorms, leading to the possibility of flash flooding, landslides, and fallen trees.
The rain will be welcomed by residents and especially farmers in the drought-stricken communities.
On Monday and Tuesday local time in New South Wales some areas west of Sydney received rain, which with the higher humidities and lower temperatures slowed the spread of fires in the area. The cooler weather will continue until Friday when the inland areas of NSW will experience temperatures over 100F, 15 percent relative humidity, 15 mph northwest winds, and a chance of dry lightning which could ignite even more fires. The hot, dry, windy weather is expected to last just for the day after which temperatures should drop back into the 80s for several days.
In other bushfire news, Australia’s government is committing an additional $2 billion over two years to a new agency tasked with rebuilding bushfire-ravaged communities.
We have known for a long time that smoke from wildfires can be harmful to humans, but in recent years that knowledge base has increased significantly. And it may have reached a new level with research conducted by fire ecologist Leda Kobziar. After learning that some snow machines use bacteria as condensation nuclei, she started to wonder if bacteria was a component of smoke. Using petri dishes and drones she collected air and smoke samples at a prescribed fire.
Below is an excerpt from an article at KQED.org:
…Then they compared what was collected to the contents of ambient (non-smoky) air. They sampled for abundance and diversity by culturing colonies and analyzing DNA.
Turns out a surprising amount and diversity of bacterial cells and fungal spores gets lofted into wildfire smoke during a fire. The more severe the burn, the more cells it transports. This is a newly emerging area of research, but Kobziar thinks these microbes have the potential to affect human health.
“There are numerous allergens that we’ve found in the smoke. And so it may be that some people who are sensitive to smoke have that sensitivity, not only because of the particulate matter and the smoke, but also because there are some biological organisms in it.” … Possibly, she says, wildfire smoke has been a driving factor in the global distribution of microbial life.
“We think that the role that wildland fire is playing in transporting organisms through smoke has probably had some influence on the evolution of species as well and development of communities,” Kobziar said.
Scientific American has produced a video that describes the formation of the fire tornado that burned and scoured a mile-long path as the Carr Fire burned into Redding, California July 26, 2018.
In the video below, click on the little square at bottom-right to see it in full screen.
There were two fatalities on the Carr Fire that day. Redding Fire Department Inspector Jeremy Stoke was burned over in his truck on Buenaventura Boulevard. On the other side of the Sacramento River, on the west side, Don Ray Smith was entrapped and killed in his dozer.
According to a Green Sheet report by CAL FIRE, the conditions that resulted in the entrapment of three dozers and the Redding Fire Department Fire Inspector that day were due to the fire tornado — a large rotating fire plume that was roughly 1,000 feet in diameter. The winds at the base were 136-165 mph (EF-3 tornado strength), as indicated by wind damage to large oak trees, scouring of the ground surface, damage to roofs of houses, and lofting of large steel power line support towers, vehicles, and a steel marine shipping container. Multiple fire vehicles had their windows blown out and their bodies damaged by flying debris.
The strong winds caused the fire to burn all live vegetation less than 1 inch in diameter. Peak temperatures likely exceeded 2,700 °F.
The Carr Fire burned 229,651 acres, destroyed 1,077 homes, and killed 3 firefighters and 5 civilians
The news media sometimes calls any little fire whirl a “fire tornado”, or even a “firenado”. These and related terms (except for “firenado”) were, if not founded, at least documented and defined in 1978 by a researcher for the National Weather Service in Missoula, David W. Goens. He grouped fire whirls into four classes:
Fire Devils. They are a natural part of fire turbulence with little influence on fire behavior or spread. They are usually on the order of 3 to 33 feet in diameter and have rotational velocities less than 22 MPH.
Fire Whirls. A meld of the fire, topograph, and meteorological factors. These play a significant role in fire spread and hazard to control personnel. The average size of this class is usually 33 to 100 feet, with rotational velocities of 22 to 67 MPH.
Fire Tornadoes. These systems begin to dominate the large scale fire dynamics. They lead to extreme hazard and control problems. In size, they average 100 to 1,000 feet in diameter and have rotational velocities up to 90 MPH.
Fire Storm. Fire behavior is extremely violent. Diameters have been observed to be from 1,000 to 10,000 feet and winds estimated in excess of 110 MPH. This is a rare phenomenon and hopefully one that is so unlikely in the forest environment that it can be disregarded.”
Thanks and a tip of the hat go out to Rick. Typos or errors, report them HERE.
Above: Mt. Laguna Observatory in Eastern San Diego County at 8 a.m. PST November 21, 2019. HPWREN.
On Tuesday the remnants of tropical storm Raymond hit Southern California and the next day merged with a cold storm that formed in the Gulf of Alaska. The result was two waves of rain, lightning, wind, and in the higher elevations, snow.
Nine weather stations in San Diego County recorded more than 4 inches of precipitation. The highest total was at Lake Henshaw with 4.68 inches. Some of the moisture became snow at Mount Laguna 6,100 feet above sea level.
Many other locations in San Diego County received more than an inch, but farther north Riverside, San Bernardino, and Los Angeles Counties had less.
This of course will pause the fire season in these areas and may be the season-ending weather event in the locations that were dumped on with multiple inches of precipitation.
Meanwhile in Northern California it was dry and very windy Tuesday and Wednesday. On Monday in the Sacramento area the Hot Dry Windy Index is predicted to be above the 95th percentile again but there is a chance of rain in the area the next day, November 26.