DREADED FLOOD OF THE SACRAMENTO. – We learn from every portion of the interior that the snow on the mountains is unusually deep, and it is the general impression that if warm weather comes upon us suddenly, with heavy rains, the floods in the valley will do much damage. Cold rains are not to be feared, for they become snow upon the mountains, and have very slight present effect upon our mountain rivers. If the snow does not soon begin to melt gradually, we may be quite sure that a sudden visitation of mild weather, with gentle south winds will bring down a quantity of water that will forcibly remind us of Sacramento floods in the early settlement of this city. Our authorities should have an eye to the signs in the heavens, and if they portend an extraordinary deluge, it will be well for them to make a general call upon the citizens to rally on the line of the levee, and do yeoman service with their picks and shovels. – Sac. Union.