Snags are dead, standing trees without leaves or needles in the crowns and present a significant threat to forest worker safety. Snags may burn through more quickly than green trees and can fall without warning. 

Live, structurally compromised green trees weakened by insects, disease, weather, fire, and age can also fall without notice.

Sawyers and crews operate with increased risk from hazard trees during low visibility or night operations. Night saw operations should include discussions involving minimizing falling operations due to reduced visibility and the reduction of situational awareness of immediate surroundings.

Environmental conditions that increase risk from hazard trees:

• Strong or gusty winds from storm cells.
• Air operations - water or retardant drops, rotor wash from helicopters.
• Steep slopes with rolling material.
• Diseased or bug-killed areas (Mountain Pine Beetle).
• Fire weakened timber.
• Reduced visibility from smoke, fog, or darkness.

Things to consider when assessing the potential danger of hazard trees in an area:

• Timbered areas that have been burning for an extended period.
• High-risk tree species (those that are known for rot and shallow root systems) in the area.
• Numerous downed trees or tree parts in the area.
• Broken tops and dead limbs overhead or an accumulation of downed limbs around tree boles (stems).
• Signs of tree decay including: cavities, splits, cracks, lack of needles, mechanical damage, missing bark, insect infestation, mushrooms, or fungus growing from tree.
• Root damage from equipment, fire, or erosion.
• Steep slopes for rolling debris, reduced personnel mobility, and more difficult size-up.
• Weather forecast with high winds or wind impacting the tree canopy.

Identify mitigation measures to reduce risk from hazard trees:

• Identify, communicate, establish, and monitor No-Work-Zones (NWZ) in all high-risk areas until the hazard has been mitigated.
• Assign qualified sawyers and falling bosses based on the complexity of the hazard.
• Consider ordering in higher complexity fallers in advance.
• Use heavy equipment or explosives to avoid placing sawyers under hazards.
• Plan quick and safe escape routes.
• Minimize exposure time at the stump by employing efficient felling procedures.
• Minimize impacts to the hazard tree from wedge pounding or other felling operations in the area.
• Do not turn your back on a falling tree or known hazard.
• Use lookouts to maintain secure felling areas. 
• Discuss/practice medical evacuation procedures and accept risk accordingly.