Wind Charts for Truckers

Wind charts for truckers provide details about wind speed levels as well as their direction. Moreover, this information is pivotal to truckers as it helps in planning trips and avoiding dangerous driving conditions. In this article, we review the impact of wind on trucks, interpreting wind charts, dot wind speed regulations, and FMCSA adverse driving conditions. 

Impact of Wind on Trucks

Generally, wind is not a major concern for road vehicles compared to snow, rain, and icy conditions. However, with trucks and trailers typically measuring 72 feet long and above 13 feet high, the center of gravity is much higher. This makes them susceptible to the impact of high winds. This impact varies according to the National Weather Service’s categorization of wind conditions in the list below.

  • None: This category refers to non-threatening and light wind speeds below 20 mph.
  • Breezy: When wind speeds are around 20 mph with occasional gusts up to 30 mph, the threat to trucks is very low. 
  • Windy: These conditions also offer low threat to trucks and occur when wind speeds are between 21 and 25 mph, with frequent surges to 35 mph.
  • Very Windy: When there are continuous wind speeds between 25 and 39 mph, the threat level becomes moderate. At this point, it may be necessary for truckers to reduce their driving speed and closely monitor the conditions.
  • High Wind: The National Weather Service considers the threat to trucks as high if wind speeds are sustained between 40 and 57 mph. Truckers will likely struggle to keep the vehicle in its lane, so driving speed should be significantly reduced.
  • Damaging High Wind: With wind speeds continually beyond 58 mph, driving is extremely dangerous, so traveling is highly discouraged. The risk of shifting cargo and overturning is prevalent in this condition.

Apart from wind speed, direction is another key component for truckers to look out for in wind charts. Headwinds may reduce the vehicle’s speed, but crosswinds offer a higher risk, with the possibility of veering and overturning. 

Interpreting Wind Charts

Ideally, truckers should review wind charts on a daily basis to help plan their trips and avoid routes with the highest crosswinds. Depending on the source, these charts come in varying formats, with some easier to interpret than others.

Wind Barbs

Wind barbs highlight the wind speed and direction on a map, thus making it easy to assess weather conditions across locations. Although they are specifically for black-printed maps, you can still find them on digital maps nowadays. The table below shows how different magnitudes of wind speeds are indicated using barbs.

Barb Speed (knots)
0
5
10
50
Barb Symbol for Wind Speed

These basic barbs can be combined when representing alternative wind speed levels as the table below shows.

BarbsSpeed (knots)
15
65
125
Barb Symbol for Alternative Wind Speed

When interpreting the direction, it is important to note that barbs always point in the direction from which the wind is blowing.

BarbDirection
From East (90°)
From South (180°)
From West (270°)
From North (360°)
Barbs vs. Orientation

Wind Roses

Wind roses are graphical charts that show the categories of wind speed in a specific location, as well as their direction. They also show the frequency of occurrence of each of these categories over a sampling period. In comparison to wind barbs, roses are easier to interpret with the data presented in a circular format.

DOT Wind Speed Regulations

The Department of Transportation (DOT) in various states has wind speed regulations to ensure safe driving in bad weather conditions. These regulations specify acceptable wind speeds for driving in line with the weight of the truck. Specific values may vary across states but generally follow the pattern in the figure below.

FMCSA Adverse Driving Conditions

According to the FMCSA, adverse driving conditions include adverse weather conditions not known to a driver before hitting the road.  These also include unusual road/traffic conditions, but not regular rush hour traffic. When any of these conditions occur, the FMCSA allows truckers to extend their 11-hour and 14-hour clocks by up to two hours. This exception ensures that drivers are not penalized for situations beyond their control, and can safely continue their trip without endangering themselves and others. There is no limit to when a trucker can use this FMCSA exception, but it is advisable to follow these steps:

  • Assess if the road or weather conditions are so severe that you are unable to safely complete the trip within normal hours of service (HOS). These conditions must be truly unforeseen or unexpected.
  • Properly document the adverse conditions using an ELD (Electronic Logging Device) or an alternative log sheet. Details should include date, time, and specific circumstances that make it impossible to complete the trip within the normal HOS. If using an ELD, then uploading pictures and videos helps as supporting evidence.
  • Notify your carrier, if applicable, of the intention to use this exception.
  • Return to duty status as soon as these conditions have passed, and comply with the HOS regulations as usual.