In many warmer and lower climates, the turn of the calendar to March signals the beginning of spring. Here in the high country, winter, with its ice and snow, will keep a tenacious grip on the landscape for many weeks to come. Despite the persistence of winter, March is a time of transition here, and the discerning observer can spot many signs that spring is, in fact, beginning. The most dependable and apparent signs of spring are in the sky, where the steady progression of the sun toward its summer zenith results in longer days and shorter nights. Wednesday will mark the equinox, when the sun's rays shine directly on the equator and nearly the entire world enjoys a 12-hour day. Moving forward, the point of most direct sunshine will continue to drift north, until it reaches the Tropic of Cancer on June 21, the summer solstice. Here in Colorado, north of the tropics, the sun will never reach a point directly overhead, but it will continue to reach higher and higher into the sky as we approach the solstice. This higher sun will shine its rays with greater intensity than the low-angled winter sun. More intense sunshine, together with warmer temperatures and longer days, means that it's a great time to start thinking about skin health, since the likelihood and the dangers from sunburns are rapidly increasing as we head toward summer.Longer days and the increasing brilliance of the sun are important signals for plants that the growing season is nearly here. The glacier lilies that will sprout at the melting feet of snowfields in late spring and summer are already preparing for their brief show. The higher angle of incoming sunshine imparts more photosynthetic energy into the snowpack and that energy is used for growth by the plants that will splash the mountains with color come summer. The persistence of snow cover is crucial for plants in early spring, since the beginning of growth also brings an increased vulnerability to extreme temperatures. Like a greenhouse, the snow serves to insulate the new buds from the bitterly cold temperatures still common on clear nights in March. The lingering snow forms a blanket that traps the relative warmth of the Earth against the ground surface, creating a pocket between the ground and the snow in which the temperature hovers near freezing and the air retains moisture. Ultimately, the persistence of snow in the early spring catalyzes the verdant colors and vivaciousness of summertime.Along with the revival of plants, the beginning of spring is also marked by an increase in the numbers and diversity of animal life around Vail. The large grazers and browsers of Colorado begin to migrate to higher elevations, following the appearance of grasses and flowers that accompanies the melting snow. That means that elk will soon be appearing in the valley, particularly on south-facing slopes and other areas where snow disappears quickly. Cow elk, in particular, will be seeking areas that offer both shelter and food as they prepare to birth their calves. And then, just as elk follow the arrival of food, predators such as mountain lions do so too. Even the opportunistic black bears converge to try to grab an easy meal of newly-born elk calf.Though the traditional signs of spring, like raging rivers and wildflowers, are still weeks away for those lucky enough to call the mountains home, we should enjoy the many blessings of this season. After all, how many people are lucky enough to welcome the spring with skis on their feet?Dylan Corbin is a Winter Naturalist at Walking Mountains Science Center. When not shredding the steep slopes of Vail, you can find him cleaning and perfecting his clarinet.