Here's why:
* Rapid Energy Release: The Helium Flash is a runaway nuclear reaction where helium fuses into carbon in the core of the star. This process releases an immense amount of energy very quickly.
* Short Duration: The energy released during the Helium Flash is so intense that it causes the core of the star to expand and cool rapidly, effectively quenching the runaway reaction within a matter of minutes.
Important Note: While the Helium Flash itself lasts only a few minutes, the process leading up to it, known as the Helium Burning Phase, can last for hundreds of thousands of years.