Brahma-astra Similar to Nuclear Weapons?

According to Mahabharata, the characters Ashwatthama and Arjun used this weapon. It is thought that the Brahmashirsha astra is the evolution of the Brahmastra, and its like a shower of meteors to annihilate the enemy. The weapon manifests with the four heads of Lord Brahma as its tip. The characters Sage Agnivesa, Drona, Arjuna and Ashwatthama possessed the knowledge to invoke this weapon. This weapon can be invoked into any object, even to a blade of grass.

In Mahabharata, it is explained that when this weapon is invoked, "It blazes up with terrible flames within a huge sphere of fire. Numerous peals of thunder are heard, thousands of meteors fall, and all living creatures became terrified with great dread. The entire sky seems to be filled with noise and assumes a terrible aspect with flames of fire. The whole earth with her mountains and waters and trees tremble." 

When it strikes an area it will cause complete destruction and nothing will ever grow, not even a blade of grass for the next 12 years. It will not rain for 12 years in that area and everything including metal and earth becomes poisoned.
Narada and Vyasa came to stop Brahmasironamaka astra used by Aswatthama and Arjuna . Arjuna and Ashwatthama unleashed their Brahmastras against each other, as Vyasa and Narada arrived to stop the collision.