What is the best training for becoming a warehouse manager? At first look, at least a BS degree in some form of business. Years of experience can be substituted but it ranges in decades. Formal education is a primary. After that, look for Lean, TQM, or something along those lines.
What types of ongoing training or certifications are necessary to be an effective warehouse manager?
Same as above. More education = better positions and pay
What do non-traditional career paths look like?
Movement in to manufacturing and accounting.
All of these are very general. Depending on your industry, it can range a bit here and there.