Material Safety Data Sheet (MSDS) is the best place to find information about the hazards that are associated with a compound. It is a document that gives the information on the potential hazards such as health, fire, reactivity and environmental and how to work safely with the chemical products.
-Rosie
One example of passive transport is diffusion, when molecules move from an area of high concentration (large amount) to an area of low concentration (low amount). Molecules are said to naturally flow down their concentration gradient
The conditions depend on the density level of the snow.
Another reason is the imperfect data gathering especially if initial results are only gathered.
The third reason is that computer models still find it difficult to see small scale phenomena.
