diff --git a/src/stcal/ramp_fitting/src/slope_fitter.c b/src/stcal/ramp_fitting/src/slope_fitter.c
index ecbd28c38..1701a458c 100644
--- a/src/stcal/ramp_fitting/src/slope_fitter.c
+++ b/src/stcal/ramp_fitting/src/slope_fitter.c
@@ -28,7 +28,7 @@ pip install -e .
 /* ------------------------------------------------------------------------- */
 static npy_intp current_integration;
 const float LARGE_VARIANCE = 1.e8;
-const float LARGE_VARIANCE_THRESHOLD = (0.01 * LARGE_VARIANCE);
+const float LARGE_VARIANCE_THRESHOLD = 1.e6;
 /* ------------------------------------------------------------------------- */
 
 /* ========================================================================= */
@@ -999,9 +999,9 @@ create_opt_res(
         struct ramp_data * rd)
 {
     const npy_intp nd = 4;
-    npy_intp dims[nd] = {0};
+    npy_intp dims[nd];
     const npy_intp pnd = 3;
-    npy_intp pdims[pnd] = {0};
+    npy_intp pdims[pnd];
     const int fortran = 0;  /* Want C order */
     const char * msg = "Couldn't allocate memory for opt_res products.";
 
@@ -1110,7 +1110,7 @@ create_rate_product(
         struct ramp_data * rd)
 {
     const npy_intp nd = 2;
-    npy_intp dims[nd] = {0};
+    npy_intp dims[nd];
     const int fortran = 0;
     const char * msg = "Couldn't allocate memory for rate products.";
 
@@ -1146,7 +1146,7 @@ create_rateint_product(
         struct ramp_data * rd)
 {
     const npy_intp nd = 3;
-    npy_intp dims[nd] = {0};
+    npy_intp dims[nd];
     const int fortran = 0;
     const char * msg = "Couldn't allocate memory for rateint products.";
 
@@ -2201,6 +2201,13 @@ py_ramp_data_get_int(
     return val;
 }
 
+#define DBG_RATE_INFO \
+    dbg_ols_print("(%ld, %ld) median rate = %f\n", pr->row, pr->col, pr->median_rate); \
+    dbg_ols_print("Rate slope: %f\n", pr->rate.slope); \
+    dbg_ols_print("Rate DQ: %f\n", pr->rate.dq); \
+    dbg_ols_print("Rate var_p: %f\n", pr->rate.var_poisson); \
+    dbg_ols_print("Rate var_r: %f\n\n", pr->rate.var_rnoise);
+
 /*
  * Ramp fit a pixel ramp.
  */
@@ -2278,6 +2285,8 @@ ramp_fit_pixel(
         pr->rate.slope = pr->rate.slope / pr->invvar_e_sum;
     }
 
+    // DBG_RATE_INFO;  /* XXX */
+
 END:
     return ret;
 }
@@ -2312,6 +2321,21 @@ ramp_fit_pixel_integration(
     return ret;
 }
 
+#define DBG_SEG_ID \
+    dbg_ols_print("   *** [%ld] (%ld, %ld) Seg: %d, Length: %ld, Start: %ld, End: %ld\n", \
+        integ, pr->row, pr->col, segcnt, current->length, current->start, current->end);
+
+#define DBG_INTEG_INFO \
+    dbg_ols_print("Integ %ld slope: %f\n", integ, pr->rateints[integ].slope); \
+    dbg_ols_print("Integ %ld dq: %f\n", integ, pr->rateints[integ].dq); \
+    dbg_ols_print("Integ %ld var_p: %f\n", integ, pr->rateints[integ].var_poisson); \
+    dbg_ols_print("Integ %ld var_r: %f\n\n", integ, pr->rateints[integ].var_rnoise);
+
+#define DBG_DEFAULT_SEG \
+    dbg_ols_print("current->slope = %f\n", current->slope); \
+    dbg_ols_print("current->var_p = %f\n", current->var_p); \
+    dbg_ols_print("current->var_r = %f\n", current->var_r);
+
 static int
 ramp_fit_pixel_integration_fit_slope(
         struct ramp_data * rd,
@@ -2330,16 +2354,16 @@ ramp_fit_pixel_integration_fit_slope(
     /* Fit slope to each segment. */
     for (current = pr->segs[integ].head; current; current = current->flink) {
         segcnt++;
-#if 0
-        dbg_ols_print("   *** [%ld] (%ld, %ld) Seg: %d, Length: %ld, Start: %ld, End: %ld\n",
-            integ, pr->row, pr->col, segcnt, current->length, current->start, current->end);
-#endif
+
         ret = ramp_fit_pixel_integration_fit_slope_seg(
                     current, rd, pr, current, integ, segcnt);
         if (-1 == ret) {
             continue;
         }
 
+        // DBG_SEG_ID;  /* XXX */
+        // DBG_DEFAULT_SEG;
+
         invvar_r += (1. / current->var_r);
         if (pr->median_rate > 0.) {
             invvar_p += (1. / current->var_p);
@@ -2374,6 +2398,8 @@ ramp_fit_pixel_integration_fit_slope(
         pr->rateints[integ].var_err = sqrt(var_err);
     }
 
+    // DBG_INTEG_INFO;  /* XXX */
+
     /* Get rate pre-computations */
     if (pr->median_rate > 0.) {
         pr->rate.var_poisson += invvar_p;
@@ -2609,6 +2635,16 @@ ramp_fit_pixel_integration_fit_slope_seg_default_weighted_ols(
     }
 }
 
+#define DBG_OLS_CALCS \
+    dbg_ols_print("sumx = %f\n", sumx); \
+    dbg_ols_print("sumxx = %f\n", sumxx); \
+    dbg_ols_print("sumy = %f\n", sumy); \
+    dbg_ols_print("sumxy = %f\n", sumxy); \
+    dbg_ols_print("sumw = %f\n", sumw); \
+    dbg_ols_print("num = %f\n", num); \
+    dbg_ols_print("den = %f\n", den); \
+    dbg_ols_print("slope = %f\n", slope);
+
 /*
  * From the intermediate values compute the optimally weighted
  * OLS fit for a segment.
@@ -2636,6 +2672,8 @@ ramp_fit_pixel_integration_fit_slope_seg_default_weighted_seg(
     seg->slope = slope / rd->group_time;
     seg->sigslope = sqrt(sumw * invden);
 
+    // DBG_OLS_CALCS;
+
     /* Segment Y-intercept and uncertainty */
     seg->yint = (sumxx * sumy - sumx * sumxy) * invden;
     seg->sigyint = sqrt(sumxx * invden);