Weather Tracker: Pineapple Express Drenches Northern California | Environment

An atmospheric river has been underway throughout the weekend, pumbling northern and central parts of California with spells of wind and heavy rain and hills and is expected to continue on Wednesday.

The weather system, locally called Pineapple Express, is created by low pressure located northeast of Hawaii, which drives moist tropical air from Hawaii and across the Pacific on blusteric west wind. The result is a stream of heavy rainfall that jumps into parts of the west coast of the United States that fall like snow down to approx. 1,200 meters (4,000ft) with rain at lower levels. A cumulative total of up to 500 mm (20in) rain is expected to have fallen by Wednesday, while up to 1.8 meters (6 ft) snow will be possible in mountainous areas. Then there has been a risk of flooding.

Further north in Canada, an Arctic air mass has brought strong catabatic wind to parts of British Columbia. Sometimes called a squamish, winding these northeast wind -cold air air through fjords and towards the west coast, strengthened in the process, and cradles up to 75 km / h. The combination of strong wind and low temperatures brought the risk of wind cooling values ​​of -20c to -25c from Saturday, and these are expected to continue into Tuesday, potentially into Wednesday. A warning for frost damage and hypothermia – which can occur in minutes under these conditions – is in place.

Areas in northeastern Queensland in Australia, especially around Townsville, have been under the weather and flood warnings throughout the weekend, which will continue in the beginning of this week.

Torrential and sustained rain throughout the weekend and early this week is expected to bring 1000 mm of rainfall, with up to 300 mm of this fall within six hours. This rainfall has caused severe floods where river levels are expected to rise to their highest in more than 50 years and possibly break records. A person is already dead as a result of the floods and thousands have been evacuated.

The severe rainfall is caused by a very slowly moving low pressure north of Australia, driving a warm and moist southeastern flow from the Coral Sea. Meanwhile, South Australia and Victoria are experiencing an intense but short heat wave with temperatures expected to reach around 40C in Adelaide Monday and Tuesday, which is more than 10C above average. The temperature in Perth is also expected to peak at over 40C.