Record-setting dry conditions in some parts of the US are raising fears of new wildfires and also could threaten drinking water supplies if substantial rain does not fall in the coming months.
Firefighters battled wildfires from California to New York on Wednesday, hampered by high winds and arid landscapes.
“Please take this seriously,” said the New Jersey governor, Phil Murphy, in declaring a drought warning on Wednesday. “We have a very dry winter ahead of us.”
Crews in California made good progress against a major wildfire in Ventura county, north-west of Los Angeles, that broke out a week ago and quickly exploded in size because of dry Santa Ana winds. The Mountain fire was 60% contained on Wednesday.
“Fire will continue to remain within containment lines with no growth predicted,” the state agency Cal Fire said in a Wednesday report, adding firefighters would be standing down there and residents would be able to return when it is “safe to do so”.
The 32-sq-mile (83-sq-km) fire forced thousands of residents to flee and has destroyed more than 215 structures, most of them houses, and damaged at least 210.
Conditions in California were “abnormally dry” but had not reached serous drought levels on most of the state, according to the Nebraska-based National Drought Mitigation Center.
Things were more difficult on the east coast, where efforts to bring a wildfire burning on the New Jersey-New York border basically stalled overnight.
The Jennings Creek fire remained 30% contained on Wednesday morning – the same as Tuesday night.
It had burned 2,283 acres in New Jersey’s Passaic county and 2,100 acres in New York’s Orange county.
US wildfire terms, explained
ShowAcres burned
US wildfires are measured in terms of acres. While the size of a wildfire doesn’t necessarily correlate to its destructive impact, acreage provides a way to understand a fire’s footprint and how quickly it has grown.
There are 2.47 acres in a hectare, and 640 acres in a square mile, but this can be hard to visualise. Here are some easy comparisons: one acre equates to roughly the size of an American football field. London’s Heathrow airport is about 3,000 acres. Manhattan covers roughly 14,600 acres, while Chicago is roughly 150,000 acres, and Los Angeles is roughly 320,000 acres.
Megafire
A megafire is defined by the National Interagency Fire Center as a wildfire that has burned more than 100,000 acres (40,000 hectares).
Containment level
A wildfire’s containment level indicates how much progress firefighters have made in controlling the fire. Containment is achieved by creating perimeters the fire can’t move across. This is done through methods such as putting fire retardants on the ground, digging trenches, or removing brush and other flammable fuels.
Containment is measured in terms of the percentage of the fire that has been surrounded by these control lines. A wildfire with a low containment level, such as 0% or 5%, is essentially burning out of control. A fire with a high level of containment, such as 90%, isn’t necessarily extinguished but rather has a large protective perimeter and a rate of growth that is under control.
Evacuation orders and warnings
Evacuation warnings and orders are issued by officials when a wildfire is causing imminent danger to people’s life and property. According to the California office of emergency services, an evacuation warning means that it's a good idea to leave an area or get ready to leave soon. An evacuation order means that you should leave the area immediately.
Red flag warning
A red flag warning is a type of forecast issued by the National Weather Service that indicates when weather conditions are likely to spark or spread wildfires. These conditions typically include dryness, low humidity, high winds and heat.
Prescribed burn
A prescribed burn, or a controlled burn, is a fire that is intentionally set under carefully managed conditions in order to improve the health of a landscape. Prescribed burns are carried out by trained experts such as members of the US Forest Service and Indigenous fire practitioners. Prescribed burns help remove flammable vegetation and reduce the risk of larger, more catastrophic blazes, among other benefits.
Prescribed burning was once a common tool among Native American tribes who used “good fire” to improve the land, but was limited for much of the last century by a US government approach based on fire suppression. In recent years, US land managers have returned to embracing the benefits of prescribed burns, and now conduct thousands across the country every year.
Greg McLaughlin, an administrator with the New Jersey forest fire service, said steep mountainous terrain and high winds, coupled with few road access points, were making it difficult to fight the blaze from the ground. A water-dropping helicopter was also being used, but the usual array of bulldozers and plows was not effective on this particular fire.
That blaze claimed the life of a New York state parks employee who was assisting firefighters over the weekend.
Dry conditions in New Jersey and New York are a growing concern, not only for firefighting efforts but for the continued availability of drinking water.
New Jersey officials declared a drought warning on Wednesday, asking for additional voluntary conservation measures, and saying they wanted to avoid imposing mandatory water restrictions.
Two major reservoirs in the state were at 51% and 45% of capacity on Wednesday, enough to keep the taps flowing, but low enough to cause concern for what might happen with additional weeks or months of low rainfall. One river that is a supplemental source of drinking water was at 14% of normal.
Murphy, New Jersey’s Democratic governor, asked people to take shorter showers, only run the dishwasher when it is full, and turn off the water while brushing their teeth.
September and October were the driest two-month period ever recorded in New Jersey. Since August, the state has received 2in (5cm) of rain when it should have gotten a foot (0.3 meters).
No significant rainfall was in the foreseeable forecast, officials said.
The ground is also bone-dry, McLaughlin added. This makes wildfires even more dangerous in that they can burn downward through dry soil and root systems, and endure for months.
On a ground dryness scale in which 800 is the highest possible score, New Jersey is at 748, meaning that the soil is dry almost 8 in (20cm) below the surface. That level had never before been reached, McLaughlin said.
A wildfire that broke out on 4 July in New Jersey’s Wharton state forest by someone using illegal fireworks has long been considered contained. But it has been smoldering underground for four months and could reignite above ground, McLaughlin said.
“We have to monitor these fires for weeks or months,” he said.
Conditions are also dry in New York, which issued a drought watch last week. Mayor Eric Adams urged residents to take shorter showers, fix dripping faucets and otherwise conserve water.
Just 0.01in (0.02cm) of rain fell last month on the city’s Central Park, where October normally brings about 4.4in (11.2cm) of precipitation, National Weather Service records show. Rohit Aggarwala, the city department of environmental protection commissioner, said it was the driest October in over 150 years of records.
Massachusetts declared a drought on Tuesday after more than a month of decreased rainfall.
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