Fog Grounded Flights in London and San Francisco on the Same Morning

Monday, November 9, opened with fog on both sides of the Atlantic. In London, at least 15 Heathrow departures were cancelled and 33 delayed between roughly 9:20 a.m. and 1 p.m., with most of the lost flights heading to UK, Irish and European cities. British Airways operated nearly all of them, including services to Belfast, Glasgow, Edinburgh, Dublin, Paris, Zurich, Milan and Frankfurt. London City lost five departures and several arrivals, some of which diverted to Stansted. Visibility at Heathrow fell to around 50 meters late Sunday night before improving through the morning.

Fog hurts Heathrow more than most airports because the airport runs close to full capacity. Under low-visibility procedures, controllers space aircraft further apart, so fewer planes can land each hour and the shortfall turns into cancellations. London City has an extra constraint: its steep approach requires specially certified aircraft and captains. The Met Office said light winds, clear skies and long nights made a near-perfect recipe for fog, and it issued another yellow warning running into Tuesday morning for parts of the Midlands, Yorkshire and eastern England.

A few hours later San Francisco International had its own problem. The FAA called a ground stop at 7:56 a.m. Pacific time, eased it into a ground-delay program, then imposed a second stop at 10:12 a.m. as low cloud lingered after the fog lifted. By about 10:30 a.m. FlightAware showed 187 SFO flights delayed and three cancelled, with average arrival delays of about an hour. Visibility had dropped to roughly an eighth of a mile around 8 a.m., and forecasters said fog could return near the Bay on Tuesday morning.

For travelers, the practical lesson is that fog season has started. In the UK, passengers on cancelled departures are entitled to a refund or a replacement flight, plus meals and a hotel if they are rebooked onto the next day, but weather counts as an extraordinary circumstance, so cash compensation generally does not apply. In San Francisco, a ground stop holds flights at their origin airports, so delays can start far from California. In both cities, checking flight status before leaving home is the simplest defense.

Sources: LBC, San Francisco Chronicle via Yahoo