Yes , U can blow them out with compress air . Sometimes this is a temporary fix ,as the end of the drain hose, there is a grommet if it is harden it will clog up again. If U do not have compress air to blow then U have to remove the front tire and then
the plastic cover under the wheel arch to locate the drain hose end grommet .It will be on the lower side just at the same level as the side kick panel(interior kick panel) U can remove this grommet and clean it and then pour water down the sunroof to make sure water is draining. The grommet looks like a tapered point with slots cut like fingers ,I cut the tip to open up a bigger gap so that fine sand and dirt will not plug it up again. As this tip sometimes harden up and will not open to allow the dirt through and clogs up the drain.
Cutting the tip will help to ensure that dirt will flow out too. Or U can replace the grommet for $8.95 from Nissan.