U.S. Postal Service Standards
Is your mailbox erected to U.S. Postal Service standards? Your mailbox should be 41" to 44" from the street to the bottom of the mailbox. The front of the mailbox should be set even with the back of the street curb.
Prepare Your Mailbox for Winter
Prior to the winter season be sure your mailbox post is solid and firmly planted in the ground. It is also important that you insure the box is securely attached to the post.
To see the correct placement of and precautions regarding your mailbox see this diagram