Give the blurbs the class equal-height-blurb and add the following to functions.php

// START equal blurbs height
(function($){
	function equalizeHeights(selector) {
		var heights = new Array();
		$(selector).each(function() {
			$(this).css('min-height', '0');
			$(this).css('max-height', 'none');
			$(this).css('height', 'auto');
	 		heights.push($(this).height());
		});
		var max = Math.max.apply( Math, heights );
		$(selector).each(function() {
			$(this).css('height', max + 'px');
		});
	}

	$(window).on('load', function(){
		equalizeHeights('.equal-height-blurb .et_pb_blurb_container');
		var iv = null;
		$(window).resize(function() {
			if(iv !== null) {
				window.clearTimeout(iv);
			}
			iv = setTimeout(function() {
	      			equalizeHeights('.equal-height-blurb .et_pb_blurb_container');
			}, 120);
		});
	});
})(jQuery);

// END equal blurbs heightCode language: JavaScript (javascript)

Note: you can also set the min-height in the blurb module to a the prefered size.