NEW YORK (NYTIMES) - As one of the worst fire seasons in Australia's history continues to engulf parts of the country, the authorities asked thousands of residents and tourists to evacuate affected areas, and the government announced the large-scale use of military assets to try and tame the fires, leaving some people stranded and those with upcoming trips to the country unsure of whether to visit or not.

Currently, fires are largely burning across the states of Victoria, where Melbourne is; New South Wales, where Sydney is; and South Australia, where Adelaide is. Military ships and aircraft have been deployed to deliver water, food and fuel to towns cut off by the fires, as well as to rescue those who are stranded.

Australian writer Richard Flanagan wrote this week that the amount of land the fires have burned is almost "as large as West Virginia, more than triple the area destroyed by the 2018 fires in California and six times the size of the 2019 fires in Amazonia".

Here is what we know about the fires and how they could affect upcoming trips to parts of Australia.

WHERE EXACTLY ARE THE FIRES AND HOW BAD ARE THEY?

Since September, the fires have burned millions of hectares across the country. The state of New South Wales has been the most affected. There have also been blazing fires in the state of Victoria. So far, at least 23 people have died, more than 1,500 homes destroyed and thousands of animals killed.

Both Victoria and New South Wales declared a state of emergency.

On the South Coast, particularly the general area from Batemans Bay to the Victorian border, vacationers were asked to leave.

People have been banned from travelling to Kangaroo Island, which lies off the coast of South Australia, and where there have been extensive fires. The island is a popular destination for Australian and foreign tourists alike.

WHAT'S CAUSING THE FIRES?

The fires and the conditions that cause them, including heat and drought, aren't new to Australians, but this season's extreme highs are. High temperatures and strong winds, combined with the long drought and low moisture in the soil, have kept fires blazing. Australia had its hottest day on record, with average highs of 41.9 deg C, in December. The extreme heat came after the driest spring on record.

In November, the state issued a "catastrophic" fire danger rating for the first time in the decade that the current warning system has been in place.

Former New South Wales Fire and Rescue chief Greg Mullins said that beginning last April he and 22 other former fire and rescue workers tried to warn Prime Minister Scott Morrison that this fire season would be an especially difficult one and it would be wise to get more water bombers. The fire chiefs were not able to get a meeting with the prime minister, Mr Mullins said.

Last week, angry residents of the Bega Valley township of Cobargo in New South Wales confronted Mr Morrison when he visited.

ARE MAJOR CITIES, INCLUDING SYDNEY AND MELBOURNE, SAFE FROM FIRES?

Although the fires haven't ravaged Sydney or Melbourne, and have mostly been in rural areas, smoke and ash have reached coastal suburbs more than 80km away, causing the air quality to severely decline.

The bush fires have created toxic pollution and choking smoke, causing the air quality index reading in Victoria to rise to more than 999 - the worst in the world last Thursday (Jan 2). Any air quality index reading over 200 is considered hazardous to health. In Sydney heavy smoke has discoloured the sky on many days, and the air quality there has at times been among the worst in the world.

In Canberra, the nation's capital, the air quality rating was over 340, leading some businesses to remain closed on Monday. (Beijing's rating was 170.)

The Australian Medical Association warned people who are sensitive to smoke, and those with pre-existing heart and lung conditions, to take extra care during the fires.

In Melbourne, people rushed to buy P2 and N95 smoke masks. People travelling to Australia should consider bringing their own.

IF I WANT TO CANCEL MY TRIP, WILL AIRLINES GIVE ME A REFUND?

If you are travelling to an area affected by the fires, you will likely be able to get a refund or have the option of rescheduling. However, if you are hoping to cancel a trip to a part of the country where there are no fires or where evacuations haven't been announced, then it's best to call your airline and talk to a representative.

Airlines including Qantas, Virgin Australia Air New Zealand and Hawaiian Airlines are keeping a close eye on the fires, they said, but for now flights are running as usual.

"We are monitoring the situation closely and will continue to address traveller concerns on a case-by-case basis," a media representative for Hawaii Airlines wrote in an e-mail.

Virgin Airlines is waiving the change fee for any guests who need to change flights because they are affected by the fire. The airline is also offering, as an alternative, a travel bank credit.

DOES INSURANCE COVER BUSH FIRES?

Not all insurance plans cover natural disasters, so it's important to read the fine print.

"If travellers do have a cancellation policy in place, their trip must still be reasonably impacted by the fires in order to cancel and be reimbursed for their trip," said Ms Megan Moncrief, chief marketing officer of squaremouth.com, a travel insurance comparison site. "This includes their destination being uninhabitable, under a mandatory evacuation, or they are prevented from reaching their destination entirely."

For those who already have trips booked, but don't have insurance, if the time allows get "cancel for any reason" insurance. These plans allow travellers to cancel a trip for any reason, including just not wanting to go anymore.

"These policies cost 40 per cent more than a standard trip cancellation policy, and only reimburse up to 75 per cent of the trip cost," Ms Moncrief said. "They also must be purchased within 21 days of the first payment towards the trip, which likely means it isn't an option for already-planned trips."

HOW DO I STAY UPDATED?

For people already in Australia and looking to stay informed, keep a radio around. Australia's national broadcaster, ABC, is offering regular updates. The Fires Near Me app, developed by the New South Wales Fire Service, is also popular among Australians.

Official maps, evacuation orders and other updates can be found on the websites for ACT Emergency Services Agency, EmergencyWA, New South Wales Rural Fire Service, Northern Territory Fire and Rescue Service, Queensland Rural Fire Service, South Australian Country Fire Service, Tasmania Fire Service and VicEmergency.