-Large tarp (material that will not absorb water)
-Scissors to cut out the stencil (palm tree shown was done free-hand, another stencil we have was printed large scale at STAPLES for $5 on paper and then traced onto tarp)
-Long rods to pin the stencil down (1.5-2ft, utilize existing metal grommets if possible, otherwise use duct tape on both sides and puncture a hole... @ 4 points on stencil is recommended but two at the top will do in a pinch.)
-Garden sprayer (we added rope handles to ours and plan on utilizing chem hand warmers attached to bottom to avoid freeze ups at nozzle)
-Rags... things may get messy
-Food Coloring and Water (always bring extra if possible)
-Bucket or Bag to carry stencils, rods, rags, etc.
-Awareness of weather... the success of this method depends on hitting the accumulated snow at the right time to ensure it is not covered up by snow or be totally melted in the morning.
This is a simple project that can yield large complex results, both visually and socially. The heart of the idea was gleaned from the street art movement that relies on "property alteration" as a means to find an interesting canvas. This method of stencil art is legal as far as the artistic expression does not venture past the point of offensive... And don't TRESPASS.
For a proof of concept, our small group tried to turn a local plaza into a more tropical space during a long and miserable cold snap. Equipped with a Palm Tree stencil cut out of a blue tarp, some metal rods to pin the tarp down to the snow banks, two garden pesticide sprayers (new-never used w/ chemicals) with our working colors, a jug of water and additional food coloring.
The photos show our success and fails.... it is advised to use liberal amounts of food coloring to darken the pigment level in solution. If the solution is too weak, the extra water need to deliver pigment creates pools and drips.
All in all this is a fun and novel way to express yourself in the winter. We have never been "hassled" by authorities and always welcomed by onlookers from the community. In addition we feel the food coloring as pigment has minimal if any impact on property or the environment.
BONUS: if you are successful and your art lasts a few days before being covered by fresh snow... be assured that when the covered work hits spring or a warm snap, it will be briefly revealed once more as the snow covering it melts layer by layer.