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There is no official wind rating on our tunnels. The caterpillar tunnel is designed to be a moveable structure. Therefore, it is inherently not made to withstand high winds.
A tunnels ability to withstand wind is based on at least 6 factors:
- Soil type
- Water Saturation
- Bracing
- Anchoring Selection
- Wind Direction
- Customer Installation
Soft soils have less grip on the anchoring materials, while more compact soils hold better.
Related to soil type is ground saturation. How wet is the soil at the time of said wind event? Saturated soil will be more likely to let go of the anchors.
The standard caterpillar tunnel is stabilized by a nylon purlin strap. Accessories that increase rigidity while maintaining the caterpillar attribute of moveable are: Steel Center Purlin, Wind Bracing, and Spring Wire.
Anchoring options that exist for caterpillar tunnels are rebar, cemented ground posts, and Earth Anchors. Rebar is the most economical industry standard effective in moderate winds. Cemented ground posts eliminates the Caterpillar Tunnel strength of temporary, but provides a rock solid foundation. Earth Anchors are an expensive ground screw option that holds like concrete but is easily removed and reused.
Tunnels have also been reported as having problems with the plastic being blown to one side from broadside winds. Spring wire is a solution to aid in preventing this occurrence.
Customer installation is the final factor. Assuming all instructions are followed and installation is correct, the standard tunnel can withstand light winds and moderate gusts.
With all that said, our standard tunnels have withstood winds up to 50+ miles per hour. In the cases where similar winds have damaged tunnels, the six factors must be analyzed.
The prudent grower would do well to evaluate these six factors in light of their budget, short and long-term farm plan, and specific growing context.
