What was the cause of the Multiple Cranes failure in the Mecca site. if cranes can Stand heavy snow storm in the Uk, why couldn't this stand the Rain?

According to the report, there were strong sand storms in Mecca prior to the accident. and additionally, hours before the disaster Mecca was experiencing medium to heavy rains. The reports said that winds of more thanKM per hour was prevailing on that time. Probably the cause of failure might be due to human errors in securing properly the crane.