cornfedcowboy

Well this is a first for me. I'm trying to extrapolate just what this is taking in to account. One would assume flights risk being cancelled if they are offering a waiver. What gives?
-Will flights be delayed or cancelled because of 105 degrees temp?
-Will ground crews call in sick and be understaffed due to heat?(it's not that hot)
-Will heat cause air to be too thin for lift on the wings at takeoff speeds?
Please help me process this folks. Maybe I'm missing something obvious.

Unusually high temperatures across the Northwest this weekend and early next week may impact your travel plans. As you prepare for your United flight, please give yourself extra time getting to and from the airport. If your plans are flexible, a travel waiver is in place to change your reservation. To change your flight or view other options, please visit the My Trips section on the United app. On behalf of all of us at United, be well.

Air Houston

Flights departing unusually hot airports may be weight restricted, I have seen that often at SLC on hit summer days. A couple years ago DL offered $1500 when looking for 15 volunteers on. CR9 flight to Knoxville, TN. It was about 102 that afternoon and SLC is over 4,000 feet elevation. But I was surprised to get notification on Thursday for a waiver for a flight next Tuesday.

WineCountryUA

Aircraft are certified for takeoff for certain combinations of altitude, temperate, takeoff weight and runway length. Higher elevations and/or higher temperature lead to less dense air and therefore less lift which requires longer runways, less weight or even no operation.

I was once at PHX and the temperatures were such (just "dry heat") we had to wait for the temperature to drop a couple of degrees before we could take off.

cornfedcowboy

I have heard about this issue in PHX on a rare occasion, or so I thought. Maybe this is more common than I realized.

raidersfan1

ACV is on the list? The highest temperature in the forecast for those dates is 63 degrees Fahrenheit!

artvandalay

The coming weather in the NW is noteworthy for its early appearance, duration and intensity. Lots of records expected to be broken.

mahasamatman

We're expecting the all-time record high for Canada to be shattered. I've seen forecasts for parts BC for Tuesday above the current record of 45°C (113°F), and forecasts tend to err on the low side here.

jsloan

https://en.wikipedia.org/wiki/Hot_and_high

Phoenix is at about 1,000 feet of elevation, and the airport has very long runways (over 10,000 feet). Several of the airports on this list are at 4,000 feet or higher, and many have shorter runways. The higher elevation means thinner air, and the shorter runways mean less time to generate lift. The net effect is that PHX can operate flights at a temperature that, say, JAC cannot.

N104UA

20mi inland from ACV it is supposed to be over 100, it could be an issue with climb performance on the aircraft, especially on UAX aircraft.

Or UA just drew a large circle across a part of the country and all airports in that circle were included.

Raymoland

For sea level airports it's a bit unusual. Arcata is short so if it gets any bit hot there could be problems. Airplanes do have maximum temperatures, usually ISA+35c or about 50c at Sea kevel. For high altitudes that maximum temperature will be lower, about 41c at SLC for example. These temps are hard limits and may totally shut down operations...

prestonh

it is likely anticipating weight restrictions with lower air density due to the high temps. This occurred a lot on the flights out of FAT in the summer (they were always taking a few bags/people off) and the temps almost always got over 100 on the reg and MSL was in the low 300's IIRC. So what used to go out as full flights in the region now likely has to have blocked out seats depending on dispatch requirements of course.

Single_Flyer

While these temperatures might be normal for other parts of the country, Seattle has never hit these temperatures (not sure about the other cities on the list). SeaTac has only hit 100 degrees three times in history. If we get to 110 like predicted, we will shatter previous historical data.

The Northwest isn't prepared for this kind of heat (like we aren't prepared for snow). Just guessing here, but the A/C air that is pumped in to the aircraft while at the gate might not be able to maintain cooling at these temperatures. May be other issues that the airports just aren't prepared for.

Here is what Alaska Airlines says on their website:

Travel to/from Seattle (SEA)

Due to extreme temperature forecasts June 25 – 28, 2021, animals will not be accepted for travel in the baggage compartment to or from Seattle-Tacoma International Airport. Pets traveling in the cabin with their owners will be accepted on all flights. For pets traveling via Alaska Air Cargo, please contact our cargo call center at 1-800-225-2752.

I'm hoping to fly out Monday afternoon, when the heat is supposed to be the worst. We will see what happens.

kevflyer

Interesting YVR isn't on the list. It's going to be 102 on Monday.

ijkh

The weather channel has Portland at 115 this weekend!!! It is going to be an inside kind of weekend.

WineCountryUA

YVR is at sea level and has long runways
08L/26R 9,940 ft
08R/26L 11,500 ft
13/31 7,300 ft


PDX runways are similar/ slightly shorted but projected to >10F hotter
3/21 6,000 ft
10L/28R 9,825 ft
10R/28L 11,000 ft

SEA but also forecast >110F for Monday
16L/34R 11,901 ft
16C/34C 9,426 ft
16R/34L 8,500 ft