Weather tracker: Deadly bomb cyclone batters north-west US

Low-pressure system brings deaths and power outages to region, while an Arctic blast sweeps swaths of Europe

Large parts of the US have been battered by severe weather this week, as low pressure developed over the north-west coast. The weather system intensified into a phenomenon known as a bomb cyclone, which rapidly intensified to an estimated central pressure of 942 hectopascals (hPa) - close to the lowest pressure recorded in that area.

To be classified as a bomb cyclone, the central pressure of a low pressure system must fall by at least 24hPa in 24 hours. Wind speeds exceeded 70mph (113km/h) near Seattle, while Canada had the strongest winds with gusts of about 100mph. There were two deaths and almost 500,000 people in the region were left without power.