No, you’re not dreaming. That is snow on the ground.
For more information about the substance, Master Stephen Pitti sent the following e-mail at 7:59 a.m. to Stilesians:
The substance falling to the ground is called “snow”. You will see more of it in the coming months. According to wikipedia: “Snow is a type of precipitation within the Earth’s atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by external pressure. Snowflakes come in a variety of sizes and shapes. Types which fall in the form of a ball due to melting and refreezing, rather than a flake, are known as graupel, with ice pellets and snow grains as examples of graupel. Snowfall amount and its related liquid equivalent precipitation amount are determined using a variety of different rain gauges.”