Final answer:
High temperatures during storage and warm weather can cause non-skid materials to slump due to softening and loss of shape-holding ability.
Step-by-step explanation:
When storage temperatures are high and the application is in warm weather, the non-skid material can "slump" or deform due to the increased temperature. This occurs because the high temperature causes the material to soften and lose its shape-holding ability. The non-skid material may become more viscous and flow under the force of gravity, resulting in a slump.