Update 3:42 p.m. ET

(Bloomberg) -- The worst cyclone in six years is set tosmash into the coast of Queensland on Tuesday morning, forcingthousands of Australians to evacuate or seek emergency shelter andprompting some of the world’s biggest miners to halt coaloperations.

Cyclone Debbie is forecast to intensify before it makeslandfall north of the city of Mackay with winds as strongas 275 kilometers an hour (171 miles per hour) at its “verydestructive core,” according to the Bureau of Meteorology. Police warned that25,000 residents need to evacuate the city due to an expected stormsurge.

'Severe cyclone'

“This is going to be a severe cyclone,” Queensland PremierAnnastacia Palaszczuk told reporters Monday. “It is increasing inintensity.”

Debbie is expected to cross land as a category four cyclone,carrying the risk of significant structural damage and dangerousairborne debris, according to the weather bureau. It will be thefirst in two years to reach the coast of the northeastern state andcould be worse than Cyclone Yasi in some areas. Yasi was categoryfive — the most severe — and badly damaged sugar- andbanana-producing regions and affected tourist sites on the GreatBarrier Reef.

115 mph winds

In U.S. terms, Debbie would be the equivalent of a Category 3hurricane — when it’s expected to hit land at about 4 p.m. NewYork time — on the five-step Saffir-Simpson scale, said JeffMasters, co-founder of Weather Underground in Ann Arbor, Michigan.He said the cyclone has begun to interact with land and hasprobably reached its peak.

“It will quickly unravel,” Masters said. “In 24 hours it shouldbe a tropical depression.”

The two countries use different methods to measure windspeed andhave their own categorical designations. According to the methodsused by the U.S., Debbie’s winds would be about 115 miles perhour.

Australia’s military is moving into position to help authoritiesrespond to the cyclone, Prime Minister Malcolm Turnbull saidMonday.

BHP Billiton Ltd., the world’s biggest miner, said it wassuspending operations at the South Walker Creek metallurgical coalmine. Glencore Plc is preparing to temporarily halt output from theCollinsville and Newlands mines. Evolution Mining Ltd., Australia’ssecond-largest gold producer, evacuated its Mt Carlton mine,according to a filing Monday.

Sugar threat

The cyclone’s footprint covers the Burdekin, Proserpine and Mackaysugar-cane growing regions, which account for about half ofQueensland’s crop, the industry group Canegrowers said in astatement. It’s too early to say whether the winds would affect thecurrent forecast for a crop of 37 million tons of sugar cane in theharvest that starts in eight to nine weeks, Paul Schembri, thegroup’s chairman said in an interview.

“It’s bound to generate some crop losses but at this point intime we can’t speculate what the extent of those losses will be,”Schembri said. “Damage now is just going to be another body blow tofarmers at this time of the year.”

Related: 10 extreme weather events of 2016

Aurizon Holdings Ltd., Australia’s largest freight railoperator, has stopped delivering coal to the export ports of AbbotPoint, Dalrymple Bay and Hay Point, the company said Sunday.

The Port of Townsville, which handles approximately $23 millionin trade per day, evacuated vessels and personnel Monday. It tookabout 40 hours before the first ship was allowed back into portafter Cyclone Yasi passed in 2011, Corporate Affairs Manager SharonHoops said by phone.

Resolute Mining Ltd. said Monday it had suspended operations andsent home staff at the Ravenswood gold mine, about 100 kilometersinland from Cape Upstart.

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