Yellow warning light flashes very briefly on hard turns

It could be the VSC.

 

Check your oil?

 

It's telling you not to corner so hard

 

Yellow triangle?

 

Wheel speed sensors have been reported to activate VSC on fast u turns due to speed difference between the inner and outer wheels. Perhaps this is the case here?

 

I've noticed that on my 2009 Gen II the VSC NagLight will occasionally blink when I'm driving a bit on the edge for the circumstances, i.e. hitting a "hump-back bridge" too fast, so the wheels are unweighted and might confuse the system by slipping or spinning. I've noticed the same happening if I drive on slippery, wet surfaces (i.e. painted lines, irons plates, ice) and accelerate too quickly.

Edit: It happens so quickly that I remember the first few times it happened, I didn't have time to register what it was, but after seeing it a few times, I was able to locate the position of the flashing light, and sure enough, there it was (…bottom row, towards the left (…I think!))

 

^ Just for reference. I'm searching the manual for an explanation of triangle with exclamation, and assuming it's yellow. Can't find anything though. Or maybe the skid symbol directly above? It'd be nice if this image was used as a visual directory in the manual. As-is the symbol explanations are scattered all over the manual, in different sections.

 

Found this: Toyota site with explanation of all the lights. You can enter your model and year to tailor what's displayed.

2010 Toyota Prius Dashboard Lights & Symbols Guide

 

are the tires all the same, with correct pressures?

 

even if oil is indeed full, too hard turns could conceivably produce momentary oil starvation. you have to record the dash to see for sure.
BTW, is it just a light or a triangle?

 

If you're regularly checking the oil, used to the idiosyncrasies of the Prius dipstick, the oil is full, case closed, lol. If you just started checking it, just to put this to bed:

With the car on level ground, remove the dipstick, wipe it, and just lay it across the engine, somewhere flat. Wait at least 10 minutes. Then reinsert, pull out and check level.

Reason being, the dipstick guide tube on the Prius seems to hang-up oil when the dipstick is first withdrawn, making for a real mess when trying to read it. Ten minutes grace gives the oil in the guide tube time to drain down.

 

Have you checked the brake fluid level? I had a leak on my previous car and initially only got warnings when going around corners. I'd expect one of the brake warning lights to illuminate too but not sure which on the US versions, and it may be less obvious than the big yellow triangle.

 

Be super nice if that useful page showed the light symbols in color. Helpful but ..could be more helpfuller