That’s leading to the creation of mountain waves, which arise when strong winds blow perpendicular to a mountain range. The waves shoot down the coastal side of the mountains, gaining speed along the way, and are more casually referred to as simple Santa Ana winds.

Dire warnings have been issued for the Los Angeles area, with a dangerous threat for the strongest wind event in more than a decade. Outages and extreme fire behaviours are major risks

The National Weather Service has issued a Red Flag waning for a wide swath of Southern California as Santa Ana winds are expected to bring dangerous fire weather to the region later this week.