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Tremors

Wood Twister at Silverwood Theme Park, Athol, Idaho. Opened 1999.

By Theme Park Spot · Last reviewed November 9, 2026

Height
100 ft
Drop
103 ft
Top speed
63 mph
Length
3,000 ft
Inversions
0
Ride time
1 min 40 s
Designer
Custom Coasters International

Tremors is a roller coaster at Silverwood Theme Park in Athol, Idaho. Built by Custom Coasters International, it opened in 1999 as a wooden twister that uses the hillside terrain.

A chain lift climbs 100 feet, and the first drop of 103 feet dives into a tunnel under the Tremors gift shop, the first of four tunnels on the ride. The park gives a top speed of 63 mph and about 3,000 feet of track. RCDB lists no inversions and a ride time of about 1 minute 40 seconds.

In 2010 Tremors was the first ride to receive topper track, and between 2020 and 2025 most of its track was replaced with steel-topped 208 RetraK track; the park reopened it in 2025 after a reworking it calls the Seismic Upgrade. Riders must be 48 inches tall, or 42 inches with an adult.

Sources

  • silverwoodthemepark.com/rides/tremors.php (Park page: wood coaster; height 100 ft; longest drop 103 ft; top speed 63 mph; track 3,000 ft; underground 4 times; opened 1999; first drop into a tunnel through the Tremors Gift Shop; 'Seismic Upgrade: Now Open'; 48 in minimum or 42 in with adult.)
  • silverwoodthemepark.com/rides/all-rides.php (Official ride list: Tremors, opened 1999; 'In 2025, you will rediscover the legend with a brand-new experience.')
  • rcdb.com/550.htm (RCDB: operating; make Custom Coasters International, designer Larry Bill; length 3,158 ft, height 85 ft, drop 99 ft, speed 50 mph, 0 inversions, duration 1:40; chain lift, four tunnels; 2020-2025 track replacement with 208 RetraK, now classified as steel hybrid.)
  • en.wikipedia.org/wiki/Silverwood_Theme_Park (Tremors, 1999, Custom Coasters International, wooden twister using the terrain; four tunnels, first under the gift shop; first ride to receive topper track in 2010.)

Numbers are from the ride's manufacturer and park where published; "n/a" means we have not confirmed that number yet. Spotted an error? Tell us.