Saying "September is usually a great time" is a pretty moot point. It's usually not well above 100 across the entire state in September.
Edited to say - I am very glad they made it out safely. If you are considering backpacking anywhere in California this summer, please remember that we are having fires in historically unprecedented locations.
Much of this trip was at 8,000 ft. Temperatures would have been about 28°F (9.6°C) lower than at sea level. From a starting base of 100°F (37.7°C), the hikers would have seen 72°F (22.2°C) temperatures --- quite comfortable. Dry air also means sweat evaporates quickly, cooling effectively.
This effect alone is a large element of the High Sierra's appeal during summertime.
https://treelinebackpacker.com/2013/05/06/calculate-temperat...
(Water freezing to boiling is 100 degrees in C and 180 degrees in F).
Though my final at-elevation result remains unchanged: 72°F / 22.2°C, a 15.5 degC drop.
https://treelinebackpacker.com/2013/05/06/calculate-temperat...
On top of that, the area where these folks were planning to hike is in alpine terrain that's relatively light in tree and vegetation cover. The likelihood of the fire consuming them was extremely low. The main hazard would be smoke from a fire nearby, which is what happened. Additionally, wilderness permits for this area are very competitive, so they had to plan this trip 6 months ago and had no ability to change the time or location of the trip.
If it's your goal to assume as little risk as possible, you're right that you probably shouldn't go backpacking (or engage in any other outdoor pursuit). You probably also shouldn't be living in California. But for most people, it's a balancing act of risk versus reward, and there's not really any evidence to suggest that these folks made a foolish or dangerous decision.
Remember, hindsight is always 20/20 and it's very easy to criticize the decisions of others from the comfort of your armchair. If you'd like to do some more of that, there are many hundreds of thousands of Californians (myself included) who also headed up into the Sierra this weekend.
This is absolutely untrue. Sure, the red flag warning set in today, but wildfire risk was considered to be at very high levels for (quite literally) weeks. See Tweets from way before the Creek Fire: [1][2][3] Just mild research would indicate that hiking (for days) deep in the wilderness would be a bad idea. It's just profoundly irresponsible. And, as someone that's done NorCal during this time previously, it's not comparable to prior years (except iirc maybe like 3 years ago when it was also a particularly hot summer).
> there are many hundreds of thousands of Californians (myself included) who also headed up into the Sierra this weekend.
There's a difference between doing some light camping or a day trip to the Sierras as opposed to hiking for several days deep in the wilderness during a heatwave.
> ...there's not really any evidence to suggest that these folks made a foolish or dangerous decision
This is the kind of shit that gets people killed. It was most definitely foolish and dangerous. Sometimes bad things happen to extremely experienced adventurers: flash floods, avalanches, etc. This was not that. It was a bunch of Instagrammers that wanted to "get away" without having any kind of respect for mother nature or what she can throw at you.
[1] https://twitter.com/R5_Fire_News/status/1302311140815298560/...
[2] https://twitter.com/NWSSacramento/status/1301932248313200640
[3] https://twitter.com/NWSLosAngeles/status/1301255674655956992...
I'm not aware of any wilderness backpacker fatalities caused by wildfires in California. The hazards here are very different than those of avalanches or flash floods, which are actually usually easier to predict. Any experienced outdoors-person knows that. You can pick a bone with them for taking photographs, but I think their decision to continue with their hike (which started before the fire had even ignited!) was much more nuanced than "there was a heat wave." If you cancelled your trip any time there was an increased risk of something, you wouldn't get outdoors very often.
Also, there's only one 's' in the plural of "Sierra." The word "Sierras" is equivalent to "mountainses." ;-)
Personally, I do not agree with your assertion that this was "a classic late season heatwave". Weather patterns in my neck of the woods were severely disrupted, and we had temperatures for days that would have been unfathomable just 10 years ago. Places in California that have never burned in recorded history are ablaze. California's firefighting forces are at a record high rate of deployment, and response times have been unfortunately diminished due to the scale of their deployments. This is not normal weather. Looking at the situation and assessing that "normally" the trip would not be excessively risky in an incomplete analysis in my opinion.
Temperatures during this heatwave were indeed impressive, but there weren't any other particularly remarkable weather patterns associated (like wind or thunderstorms), that was the point I was trying to make. I never said it was normal, just that it wasn't as extraordinarily risky as many in this thread are claiming.
