Sunday morning, D/FW Airport dipped to 37 degrees, the coldest temperature recorded so far this fall season. And much of rural North Texas dropped to freezing for the first time.
Remember, the official temperature is recorded at six feet above the ground, at about head height. But cold air is dense and sinks, so the temperature will almost always be colder at ground level. Whenever you see ice, you can be sure that the temperature is at 32 degrees or colder, no matter what the official temperature reads.
So frost is common, even when official temperatures are in the middle or even upper 30s. But not all frost is the same.
This weekend, Jamie Moore, the emergency management coordinator for Johnson County, captured a few exquisite photos of frost flowers that he saw at his farm.
These frost flowers typically form only in late fall or early winter, when the air drops to freezing. But the ground is still warm, and living plants have not previously been subjected to freezing temperatures. Water in the plants' stems is still liquid, and as the temperature first reached freezing, that water began to freeze, opening tears in the stem. The water then slowly oozes out, forming the shapes of flowers, swirls and amazingly beautiful ice sculptures.
Here is a link to some more examples of frost flowers.