Buffalo Blizzard® Blizzard Blocks Helps Secure Winter Covers On Swimming Pools – Choose Quantity. Buffalo Blizzard® is an attractive way to keep your pool’s winter cover in place all season long. The hard high-density black polyethylene material construction offers a more durable solution when compared to vinyl water bags, which may rupture or leak. Keep your winter cover securely in place in a more durable and aesthetically pleasing way than with water bags. The Buffalo Blizzard® Blizzard Blocks offers a more durable solution when due to its hard-plastic construction. Simply place the Buffalo Blizzard® Blizzard Blocks around the edge of your pool cover, fill about ¾ with water, snap on the top lid and you’re set for winter! When spring comes back around, just take off the lid and tip the blocks to drain. Easy to use and better looking, forget vinyl water bags next winter and turn to these. Survive the toughest winters due to being made from high-density polyethylene material. Infused with UV inhibitors and will not fade or crack. Modern, appealing design to compliment your pool while helping to keep it safe. Easy to store, nesting design, allows you to stack the blocks and take up minimal room. Can be used with any pool type. Inner dimensions: 36″ L x 6″ W x 4 H. Approximate Blocks Needed by Pool Size. Pool Size 12′ x 20. Pool Size 12′ x 24. Pool Size 14′ x 28. Pool Size 16′ x 24. Pool Size 16′ x 32. Pool Size 16′ x 36. Pool Size 16′ x 40. Pool Size 18′ x 36. Pool Size 18′ x 40. Pool Size 20′ x 40. Pool Size 25′ x 45. Pool Size 25′ x 50. Pool Size 30′ x 50. Pool Size 30′ x 60.