How a foreman decides whether the crew works, adjusts or stands down, and the free tool that does the math for any US jobsite. Written by Errol Kerr, a Truckee excavation foreman.
Short version. Pick limits for wind, rain, lightning, heat, cold and snow before the day starts. If every reading is inside the limits, it is GO. If something is close, it is CAUTION. If a limit is blown, it is NO-GO. The free Crew Weather tool does this for any ZIP code and shows the call for each day of the 16-day forecast.
| Call | What it means on site |
|---|---|
| GO | All readings are inside the crew's limits. Work as planned. |
| CAUTION | A reading is near a limit. Re-sequence the day, shorten exposure, move the risky task earlier or later. |
| NO-GO | A limit is exceeded. The affected work stops or moves to another day. |
The Crew Weather tool picks a preset by climate zone, then every number can be changed. The mountain preset, which fits Truckee and the Sierra, starts here.
| Reading | Mountain preset |
|---|---|
| Max wind | 25 mph |
| Max rain chance | 50 percent |
| Max total precipitation | 0.5 inch |
| Min temperature | 25 F |
| Max temperature | 89 F |
| Snow flag | 2 inches |
These are starting points, not safety rules. Your company policy, the equipment manufacturer and OSHA or Cal/OSHA requirements come first.
It blends eight weather models, layers the HRRR over the first 18 hours, and checks the result against your limits for each hour and each day. The blend is graded every day against the Truckee airport station, and the error is published openly on the forecast accuracy tab. For Truckee and the Sierra, see the Truckee weather forecast and the Kerr Storm Tracker, errolkerr.com's own future radar.
GO means conditions are inside the crew's limits and work proceeds as planned. CAUTION means one or more readings are close to a limit, so the foreman adjusts the plan, shortens exposure or moves the risky task. NO-GO means a limit is exceeded, such as damaging wind, lightning nearby, extreme heat or a hard freeze, and the affected work stops or is rescheduled.
Common limits are sustained wind and gusts, rain chance and total rain, lightning within a set distance, high and low temperature, and snowfall. The Crew Weather tool starts from a preset for the jobsite's climate zone. For mountain jobsites the preset is wind 25 mph, rain chance 50 percent, 0.5 inch total precipitation, a low of 25 F, a high of 89 F and 2 inches of snow. Crews can change every number, and company policy, the equipment manufacturer and OSHA or Cal/OSHA rules come first.
It blends eight weather models, layers the HRRR over the first 18 hours, and compares the result to the crew's thresholds for each day and hour. The blend is checked daily against the Truckee airport station, and the published error is at errolkerr.com/weather#accuracy.
Yes. errolkerr.com/crew-weather is free, needs no signup and works for any US location by ZIP code.
No. It is a decision aid. The foreman on site, the safety plan and the applicable regulations make the final call. Lightning in particular is a stop-work event: when thunder is heard, go to shelter and follow your site lightning procedure.