How can blockage impact the flow of blood?

You could have a heart attack.

Explanation:

When plaque builds up, it narrows your coronary arteries, decreasing blood flow to your heart. Eventually, the decreased blood flow may cause chest pain (angina), shortness of breath, or other coronary artery disease signs and symptoms. A complete blockage can cause a heart attack.

and after water is usually warmed by the sun the water temperature raises and then evaporates .