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Seventeen Hours of Thunderhill

Thanks to heavy fog, the 2021 25 Hours of Thunderhill was interrupted mid-race and became the seventeen hours of Thunderhill. Otherwise, the race was run under sunny blue skies and warm temperatures (at least warm in December Thunderhill terms). The 2020 race was cancelled so it had been two years since the last running in 2019 (which was a rainy affair).

Thirty six cars took the green flag, a smaller field than historical norms of mid to low 50 entries.

More to come about the race in general (keep an eye on our Instagram account at @rennphoto as well), but if you're looking for a story within the race, consider the #18 Teen Mazda Challenge entry. Five young drivers steered their Mazda Spec MX-5 to a 20th place overall finish. A selection of photos has been posted in the Gallery. Congrats to the team. To view, click on the photos above or below.

Five general race observations:

1) Great to see so many crews and drivers take a keen interest in other cars in the paddock as enthusiasts first and competitors second. Racers like race cars and there is enormous respect and appreciation across makes and models.

2) Mazda, BMW and Honda badges comprised two-thirds of the field. Grassroots racing truly owes much of its foundation to these marques. Surprisingly, no Porsches found their way to the 2021 race.

3) Fog moves quickly. The sun set at 4:46pm under clear skies. Traces of fog started to show beneath the paddock lights by 5:24pm. When the safety car began to circulate at 5:49pm for a scheduled corner worker change, visibility was still reasonable but clear skies had disappeared. There was no indication that fog was an issue and the field was preparing for a restart. In only three minutes starting at 5:55pm, the fog began to overcome Turn 5. The safety car continued to lead the field around the track. At 6:11pm, tail lights were barely visible in Turn 6 to those standing on pit lane. At 6:16pm, cars rolled to a halt on the front straight for the red flag. Racing resumed just under 11 hours later. Thunderhill rules explicitly allow officials to extend the race for up to 3 hours to make up for fog-related race suspension, so the race ended at 3pm instead of noon.

4) Fog it also highly localized. On Sunday morning, racing resumed while heavy fog shrouded the nearest town of Willows - only 8 miles away from the track. A weather curtain perhaps a mile or two from the track separated bright blue sunny skies from low ground fog that slowed road traffic to a crawl.

5) Perhaps light traffic density helped to minimize contact. There was some modest contact here and there, but reliability issues were a greater threat.


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