How Much Wind Is Too Much Wind?

It was a dark and stormy night. Literally. On February 7th, the National Weather Service issued the following special weather statement for our area:

Wind gusts up to 50 mph. And a Tornado watch.

What to do?

This academic paper (pdf download) holds some interesting information for RVers.

First, when driving (minimum overturning wind speeds when the wind is perpendicular to the vehicle) all it takes is a wind speed of 53 mph to overturn a 20-foot travel trailer and, for a 30-foot motorhome, all it takes is a wind speed of 65 mph.

The researchers do point out that the literature is sparse and based largely on equations for wind pressures and forces applied to vehicles of a given geometry. If the wind is gusting north of 65 mph, then it is best to avoid driving a large motorhome.

Second, when stationary.

For F0 wind speeds of about 34 m/s (75 mi/hr), there should be no reference to vehicles in damage descriptions because they are not expected to be moved or tipped by the wind.
For F1 winds speeds of about 43 m/s (95 mi/hr), “Semi-trucks and other high profile trucks, trailers, and buses may be tipped over; cars, vans, and pickups are not tipped.”
At F2 wind speeds of about 56 m/s (125 mi/hr), “Cars, vans, and pickups may be moved but fewer than 10% are tipped over.”
At F3 wind speeds of about 70 m/s (155 mi/hr), “Cars, vans, and pickups are moved and 10% to 50% are tipped over. Vehicles that are tipped over may be rolled or lifted and thrown.”
At F4 wind speeds of about 90 m/s (200 mi/hr), “More than 50% of cars, vans, and pickups are tipped over. Vehicles that are tipped over may be rolled or lifted and thrown.”

The authors of the report do make the following conclusion:

Whether a severe wind will upset a stationary vehicle may depend on the vehicle weight and shape, progressive damage, impacts of debris, wind gusts, direction and duration of wind, and exposure.

The gusts were pretty strong that night. Not strong enough to tip us over. And not strong enough to cause any damage.

This scale might be helpful. If wind speeds were to exceed 65 mph, we would bring the slides in, lock up the coach and find a suitable shelter to ride out the storm.