The not-always-annual natural phenomenon known as the "firefall" at Yosemite National Park's Horsetail Fall is happening through this weekend.

The event, which SFist last took note of via a flurry of Instagrams in 2016, occurs when the sun sets at a particular angle during the middle two weeks of February. But in order for the spectacular glowing effect to happen, skies have to be clear and there has to be enough water running over the falls — so for several years during the drought there was no "firefall."

Central Valley-based photographer Vaché Geyoghlian captured the images below on Tuesday (hit the arrow at the right for a close-up).

ABC 7 reports that heavy snow in Yosemite and a list of parking and stopping restrictions means that getting to the perfect vantage point to see the "firefall" could be "tricky." Visitors will need chains for their tires, as well as gear to help them hike through snow.

Below, several more images captured in the last week by photographers at Horsetail Fall.

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Well, it's that time of year again ... you guessed it, it's Yosemite Firefall season! Not sure how it's going to play out this year with cold weather and round after round of snow forecast over the next week but regardless, we will not be there. Just aren't ready to tackle the crowds again but for those who haven't seen Horsetail Falls transformed by the setting sun during the last couple of weeks in February, its well worth the effort to do so. We got one stab at it a few years ago in 2016 (and by that we mean, we drove overnight, with a lot of paring along the way, for one afternoon of viewing before immediately leaving and going straight back to Phoenix) and got very lucky. The display of light played out through all it's stages, including the deep red phase at the very end and it was truly a surreal sight to witness. This was just before the red stage, when the waterfall turns a brilliant orange and it is our contribution to the onslaught of Firefall photos that have already been and have yet to be, posted. Is anyone planning on trying to go this year? #firefall #yosemite #yosemitenps #yosemitewinter #waterfall #yosemitefirefall #nationalparks #nationalparkgeek #landscapephotography #sunset #itsamazingoutthere #visitcalifornia #photographyworkshop #stunnersoninsta #westbysouthwest #igsouthwest #roadtrip #horsetailfalls

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FIREFALL! 🔥Last night we FINALLY saw the ever-elusive Firefall in Yosemite. We can finally check this one off our bucket list! ✔️⁣ ⁣ We have been on the hunt to see this wonder for years, and we’ve tried several times without any luck. The conditions need to be just right in order to see it. ⁣ ⁣ First, there needs to be enough water to make Horsetail Fall. The droughts in Cali have made that difficult in years past. One year ago we made the long haul up only to find out the fall was dry. 😔⁣ ⁣ Second, the sun angle is only right for a few days in February and October. October usually doesn’t have enough water to make the fall, so the window of opportunity is February. ⁣ ⁣ Third, clear skies! This was the challenge this year. We attempted to see the fall two nights before this one, and blizzard or cloudy conditions obscured it. The third time was the charm though! It was worth the wait and effort! #magical 😍 ⁣ ⁣ Check out our story for the video footage! ⁣

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Previously: Yosemite 'Firefall' Phenomenon Delights Photographers