The Vaishaka Mahotsavam, a 28-day festival held in the heart of a dense forest by the roaring River Bavali, offers an unparalleled experience unique to Kerala. Hosted by the Kottiyoor temples-Akkare Kottiyoor and Ikkare Kottiyoor-situated on the banks of the mighty River Bavali, in Kannur district, this festival is among the most cherished in Northern Kerala. The Akkare Kottiyoor Temple, the primary venue, opens only during the festival days annually, from the Chothi asterism of the Malayalam month of Edavam to the Chithira asterism of the Malayalam month of Midhunam, typically falling between May and June.

Devotees worship a swayambhoo lingam (self-created idol of Lord Shiva) placed on a platform made of river stones, known as manithara. The rituals begin with Neyyattam (pouring of ghee), initiated by bringing a sword from Muthirerikavu in Wayanad. A captivating ritual is the Rohini Aaradhana, where the priest embraces the swayambhoo Shiva linga. Another significant ritual is the Elaneer Vayppu, where devotees offer tender coconuts before the swayambhoo lingam. The festival concludes with Elaneerattam, where the head priest pours the collected tender coconut water over the idol.

The Kottiyoor festival is deeply rooted in mythology and cultural traditions. According to legend, the temple is situated where the ancient Daksha Yaga took place. Sati, consort of Shiva, immolated herself in the yagna fire, and enraged by her death, Shiva created Veerabhadra who destroyed the yagna and killed Daksha. Later, the Gods, including Brahma and Vishnu, pacified Shiva, leading to the restoration of the yagna and the granting of moksha to Daksha, who was resurrected with a goat's head.

The Akkare Kottiyoor Temple, open only during the festival, is notable for its absence of a formal structure, with the deity placed on a natural stone platform. The Ikkare Kottiyoor Temple, located across the river, remains active year-round. The picturesque setting of the temples amidst the Sahya mountain range and the medicinal waters of the Bavali River adds to the festival's allure.

The Vaishaka Mahotsavam features numerous rituals and events, including the bringing of a sword from Muthirerikavu, Bhandaram Ezhunnallath (transporting gold, silver vessels, and ornaments from Manathana village to Kottiyoor), Elaneer Vayppu and Elaneerattam (offering and pouring of tender coconut water over the idol), Rohini Aaradhana (priest embracing the swayambhoo Shiva linga), and Ezhunnallippu (procession with idols of Lord Shiva and Parvathi carried by elephants). An important part of the festival is Aanayootu, the ceremonial feeding of elephants.

The Vaishaka Mahotsavam, celebrated in the Malayalam month of Edavam & Midunam (May-June), attracts over 100,000 participants, making it a significant event in the cultural calendar of Kerala. The festival's combination of spiritual fervor, vibrant rituals, and the natural beauty of its setting provides a unique and deeply enriching experience for devotees and visitors alike.