Passengers

Passengers queue at the Virgin Blue check-in counter at Sydney's domestic airport after some flights were cancelled due to volcanic ash on June 13, 2011. ( REUTERS/TIM WIMBORNE)

Here we go again. 

Last week, ash from the Cordon Caulle volcano in Chile grounded hundreds of flights and stranded tens of thousands of passengers when it hovered over several Australian cities and New Zealand. By Friday, all flights were running normally, but the ash cloud has lapped the globe and is soon expected to cause more problems.

On Monday, Virgin Australia and budget carrier Tiger Airways announced they would cancel Tuesday flights to and from the South Australia capital, Adelaide. National carrier Qantas and its subsidiary Jetstar suspended morning flights into and out of the city. The airlines also suspended service to some smaller nearby cities.

Qantas won't fly to Adelaide or the regional town of Port Lincoln between 6:30 a.m. and 2 p.m. local time on June 21, the Sydney-based airline said in a statement on its website. The carrier has said that it will, however, operate five early-morning flights.

Tristan King, a meteorologist with the Volcanic Ash Advisory Center in Darwin, Australia, said on Monday that if the ash stays on its current course (and doesn't dissipate) it could eventually disrupt air traffic in Sydney, Melbourne, and the country's capital, Canberra.

The ash cloud is forecast to descend below 20,000 feet (6100 meters) and affect flight paths.

On the bright side, experts in Chile said on Sunday that the Cordon Caulle volcano, which began erupting on June 4, is becoming less active.

Curious why airplanes can't fly through ash?  Click HERE