A 70 mile-per-hour wind is a significant threat to life and property. Wind speeds at this level are far beyond what most people experience in a typical storm, transitioning from a nuisance to a destructive force capable of causing widespread damage. The danger is not confined to coastal areas, as severe straight-line winds from thunderstorms can easily reach this velocity inland.
Placing 70 mph Winds on the Scale
The danger of a 70 mph wind is clearly illustrated by its classification across official weather scales. On the Beaufort Wind Scale, which assesses wind effects on land and sea, 70 mph falls within Force 11, known as a “Violent Storm.” This category is associated with widespread structural damage and is rarely experienced inland outside of severe weather events.
The National Weather Service (NWS) considers a thunderstorm capable of producing 70 mph winds as a “considerable damage threat.” This speed is significantly higher than the 58 mph threshold required for a standard Severe Thunderstorm Warning. When a warning carries this “considerable” tag, it signals a distinct escalation in danger and the potential for greater property destruction.
A sustained wind speed of 70 mph falls within the range of a named Tropical Storm (39 to 73 mph). Furthermore, this speed is only marginally below the 74 mph minimum required for a Category 1 hurricane on the Saffir-Simpson Hurricane Wind Scale. This proximity to hurricane force demonstrates the extreme kinetic energy packed into a 70 mph wind event.
Immediate Threat to Structures and Landscape
Wind at this velocity applies immense pressure, creating a threat to stationary objects and the natural environment. Structural damage often begins with the failure of exterior components, such as the peeling away of roof shingles, siding, and gutter systems. Poorly constructed outbuildings, like sheds or detached garages, are susceptible to partial or complete failure under the sustained force of these winds.
Seventy mph winds easily snap large tree limbs and uproot mature trees with shallow root systems. This tree damage is the primary cause of utility disruptions, as falling trees and branches tear down power lines and utility poles. The resulting power outages can be extensive and last for days, complicating recovery efforts.
Unsecured items outdoors instantly become dangerous projectiles, capable of shattering windows and penetrating walls. Construction sites are vulnerable, with scaffolding, loose materials, and temporary structures often collapsing or being launched. The volume of debris—from structural fragments to natural materials—contributes to widespread destruction and makes travel treacherous.
Navigating Personal and Travel Risks
The force of a 70 mph wind makes standing or walking outdoors nearly impossible. The wind pressure can quickly lead to a loss of balance, resulting in falls and potential injury from contact with the ground or wind-borne debris. Any person caught outside is immediately at risk from falling trees, collapsing signs, and flying materials.
Driving during such a wind event is dangerous, especially for high-profile vehicles like tractor-trailers, box trucks, and recreational vehicles (RVs). These vehicles present a large surface area, making them prone to overturning completely. Even standard passenger cars can be difficult to control, as gusts push them laterally and debris reduces visibility.
The risk of injury is heightened by the potential for infrastructure failure, such as the collapse of traffic signals or the snapping of power poles. Traveling exposes occupants to the direct impact of heavy debris or the possibility of encountering impassable roads. Therefore, travel should be avoided entirely once winds approach this dangerous threshold.
Essential Safety Measures
Preparation for a high-wind event begins by securing anything outdoors that the wind could lift. This includes bringing in patio furniture, trash cans, and garden tools, or firmly tying down large items like trampolines and grills. Inspecting and clearing gutters also helps minimize water damage if the wind event is accompanied by heavy rain.
During the storm, the safest place is inside a sturdy structure, specifically in an interior room on the lowest floor, away from all windows and glass doors. Windows are a significant weakness against high winds and flying debris. Continuously monitor official weather alerts from the National Weather Service on a battery-powered device.
After the winds subside, exercise caution before venturing outside to assess damage. Assume that any downed power line is live, and never attempt to move or drive over them. Report downed lines and significant debris to local authorities, and be mindful of weakened or partially fallen trees that could collapse without warning.