So after the snowfall in Dallas the other day, and looking at the NWS daily weather summary for the day, does the precipitation report include snowfall? I would think snowfall is considered precipitation, so it should be included, but I know they have a separate section for snowfall and precip. I ask this because the snowfall report for DFW Airport was .3 inches, but the precip report was only 0.05 inches. I read somewhere online where you need to divide by 10 to convert a snowfall total to a rainfall total, but it appears there was also rain from that day too.
When you have snow, you must melt what was collected in the gauge to get the liquid equivalent, which is reported as the precipitation. However, you can never assume a 10:1 snow-liquid ratio! It has been proven over and over that this ratio can vary widely with time and space. Snow is generally drier as it gets colder, so the snow-liquid ratio increases. Furthermore, you have to account for the microphysics involved in snow growth along with your moisture source. Wet snow right near the freezing point can be down at 3:1. At the other extreme, dry snow in the Rocky Mountains and lake-effect snow in the Northeast have reached up to 100:1. The 10:1 ratio is just a common average that was thought to be a rule of thumb, but we have learned better thanks to modern research. The liquid equivalent of 0.05" looks good to me as it gives a 6:1 ratio, and your area was just below freezing when it snowed at DFW.
