Few sounds are sweeter than the plink of spring rain on a tin roof. And a hard rain, said Pat Munoz, organizer of a late-March voyage to Virginia's Blue Ridge, "is music to a paddler's ears."

Unfortunately on this weekend, the hard rain came a little late. And if the little Rose River outside the log cabin at Graves Mountain Lodge had increased in volume by morning, the change was imperceptible. There were still more rocks than water.

But plenty of other little creeks were runnable that weekend, still high enough from earlier rains to make passage possible by canoe or kayak.

There were the Thornton and the Hazel, the Hughes and the Robinson to explore -- all clear mountain creeks slashing east out of the stony Blue Ridge on the way to the Chesapeake.

We chose the Thornton and enjoyed a splendid morning during which no other boats were spied. There was a lunch on a flat rock: bouillabaisse warmed over a driftwood fire, sandwiches and wine.

Icicles hung from the rocks on the dark side of the valley but the breeze was mild. When we launched for Phase 2, we warned one another of the "after-lunch syndrome," when things look so rosy the paddler loses sight of the perils of little water.

Which must explain how my kayak came to slide bow-on over a half-submerged tree. In seconds, the stern had swung around to pin itself on the trunk, the fast water rushing all around. I rocked the little boat and went kersplash for a frigid bath.

No matter. On small streams the shore is a few feet away, and the water is rarely deeper than waist-level. Equipped with a wetsuit or a change of clothes in a dry bag, the properly outfitted paddler can be back on the water, unharmed, with a story to tell back at the cabin.

That's the beauty of small streams and now's the time to enjoy them, when the redbuds are ready to burst and the bluets flower in the meadows. By late May, spring rains will have passed and the Robinson, Hughes, Thornton, Hazel and their kin will be better suited to whitewater hiking, which is no fun at all. PADDLE GUIDES -- A little research is in order. There are several guides for spring paddlers -- books giving locations of appropriate streams and data on correlating river- gauge information (available by dialing 899-3210) to tell whether there's enough water before tackling a two-hour drive. Among them: "Virginia Whitewater" by Roger Corbett; "Maryland and Delaware Canoe Trails" by Ed (Boulderbuster) Gertler, and "Wildwater West Virginia" by Bob Burrell and Paul Davidson. All are available through the American Canoe Association's book service at P.O. Box 248, Lorton, Virginia 22079. It's vitally important never to tackle any whitewater river, particularly in cold weather, without someone along who's a qualified paddler with knowledge of stream conditions. There are always surprises on little- used rivers -- trees blow down and block the stream, creating dangerous conditions like the one that capsized him-who-thought- he-knew-what-he-was-doing. RIVER TRIPS -- The American Rivers Conservation Council, for which Pat Munoz serves as trip coordinator, has scheduled three April voyages that will be overseen by experts. ARCC will do the Dry Fork of the Cheat by raft on April 16 ($40 per person); Rappahannock at Kelly's Ford by canoe April 17 ($17); and the Cacapon near Cacapon Bridge by canoe April 30 ($26), all with boats provided. Call 547-6900 for information. CANOE CANOE? -- The venerable Canoe Cruisers Association is always looking for new members to join its chaperoned trips every weekend. Call the Hotline at 656-2586 or write P.O. Box 572, Arlington, Virginia, for information. There's one certain advantage to joining the swollen ranks of Washington's paddling community: When it rains all weekend, you can smile a merry smile.