My cousin and I see it everytime we go west on the 210 freeway staring in Irwindale. We can see the flashing light change colors

This happens everytime I go to work at around 10 40 am. On the 210 freeway going west. It started when me and my cousin enter irwindale and ends as we get close to Monrovia. We notice it flashing colors starting red, orange, green and then blue. It is so bright is shines through the day. The flashing color light use to last about 30 seconds but gets shorter everytime. I pull out my phone to film but because my phone is so old, the camera takes a minute to load so I end up missing the light.
The light seems to be happening in the San Gabriel Mountains close to those spires at the top of the mountain where the old observatory is, I would assume but looking, I could be wrong.
We have only seen this flashing colored light 3 times this year.